Final edit at the top for visibility: Thanks to IInspectable for the suggestion, targeting the specific window DC is much faster, less than a second.

def get_win_px(x=0, y=0, name="Device Manager"):
    hwnd = win32gui.FindWindow(None, name)  # warning no error handling
    hdc = win32gui.GetWindowDC(hwnd)
    color = win32gui.GetPixel(hdc, x, y)
    win32gui.ReleaseDC(0, hdc)
    return color

Using timeit to get an idea of how long each approach takes to execute.

Testing shows win32 is fastest on my PC, as you've also found:

get_px_ctypes:    16.759 ms
get_px_win32:     16.689 ms
get_px_pya:       16.798 ms
get_win_px:        0.970 ms
press_win32:       4.701 ms
press_pya:       104.358 ms
dpress_win32:     54.339 ms
pressed_win32:     0.031 ms
pressed_kbd:       5.729 ms

Note that press_win32 has no delay between key down and up events, dpress_win32 has a 50ms delay after the key down event. The delays after the key down event are probably not impacting the key detection in your game and might prevent duplicate key presses for the same colour bar.

Interestingly the get pixel functions are comparable.

So I would recommend an approach without the check for Q to exit, use Ctrl+C instead, keboard.pressed() adds ~6ms per loop.

It's not clear what benefit looking at multiple pixels provides; it opens the possibility of missing the first location check when checking the second if the bar moves fast enough.

Profiling indicates most of the time is spent in threads waiting for a lock or the response to be added to a queue. I've excluded calls below whose total time is less than a millisecond. This is not exciting or actionable information, other than to guide us to seek an alternative avoiding the full desktop.

>>> import cProfile
>>> cProfile.run("detect_and_press()", sort='time')
         47528 function calls (46822 primitive calls) in 657.508 seconds

   Ordered by: internal time

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
4941/4236  637.206    0.129  637.384    0.150 {method 'acquire' of '_thread.lock' objects}
      705   19.867    0.028  657.260    0.932 threading.py:323(wait)
      2/1    0.180    0.090    0.017    0.017 {built-in method builtins.exec}
      706    0.096    0.000    0.160    0.000 _winkeyboard.py:498(process_key)
      705    0.020    0.000  677.175    0.961 queue.py:154(get)
      706    0.019    0.000    0.162    0.000 _winkeyboard.py:531(low_level_keyboard_handler)
        1    0.017    0.017    0.017    0.017 test_px_access.py:33(detect_and_press)
      706    0.015    0.000    0.051    0.000 __init__.py:222(direct_callback)
     1412    0.010    0.000    0.010    0.000 {method 'release' of '_thread.lock' objects}
      706    0.008    0.000    0.008    0.000 {built-in method _thread.allocate_lock}
      706    0.007    0.000    0.010    0.000 __init__.py:211(pre_process_event)
      706    0.007    0.000    0.027    0.000 queue.py:122(put)
     1412    0.006    0.000    0.006    0.000 {built-in method builtins.sorted}
     2118    0.005    0.000    0.020    0.000 threading.py:394(notify)
      706    0.004    0.000    0.013    0.000 _keyboard_event.py:24(__init__)
      706    0.004    0.000    0.008    0.000 _canonical_names.py:1233(normalize_name)
      706    0.003    0.000    0.009    0.000 queue.py:57(task_done)
     2118    0.003    0.000    0.005    0.000 threading.py:302(__exit__)
     2824    0.003    0.000    0.003    0.000 {built-in method builtins.len}
     3530    0.002    0.000    0.002    0.000 {method '__exit__' of '_thread.lock' objects}
     2824    0.002    0.000    0.006    0.000 threading.py:314(_is_owned)
      706    0.002    0.000    0.002    0.000 {built-in method builtins.all}
     2118    0.002    0.000    0.003    0.000 threading.py:299(__enter__)
     1412    0.002    0.000    0.003    0.000 queue.py:209(_qsize)
     2118    0.002    0.000    0.002    0.000 {method '__enter__' of '_thread.lock' objects}
      706    0.002    0.000    0.002    0.000 {method 'get' of 'dict' objects}
      706    0.002    0.000    0.003    0.000 threading.py:311(_acquire_restore)
      706    0.001    0.000    0.001    0.000 {built-in method time.time}
      706    0.001    0.000    0.003    0.000 threading.py:424(notify_all)
     1190    0.001    0.000    0.001    0.000 {built-in method builtins.isinstance}
      484    0.001    0.000    0.002    0.000 __init__.py:135(is_modifier)
      706    0.001    0.000    0.002    0.000 queue.py:217(_get)
      706    0.001    0.000    0.001    0.000 queue.py:213(_put)
     1412    0.001    0.000    0.001    0.000 {method 'append' of 'collections.deque' objects}
      372    0.001    0.000    0.001    0.000 {method 'lower' of 'str' objects}
      706    0.001    0.000    0.001    0.000 {method 'popleft' of 'collections.deque' objects}
      706    0.001    0.000    0.001    0.000 threading.py:308(_release_save)
      706    0.001    0.000    0.001    0.000 {method 'remove' of 'collections.deque' objects}

Full Code listing, edited to include release of device context handle:

import ctypes
import time
import win32api, win32con, win32gui
import pyautogui
import keyboard


def get_px_ctypes(x=0, y=0):
    hdc = ctypes.windll.user32.GetDC(0)
    color = ctypes.windll.gdi32.GetPixel(hdc, x, y)  # & 0xFF # AND to isolate red portion
    ctypes.windll.user32.ReleaseDC(0, hdc)
    return color

def get_px_win32(x=0, y=0):
    hdc = win32gui.GetDC(0)
    color = win32gui.GetPixel(hdc, x, y)  # & 0xFF # AND to isolate red portion
    win32gui.ReleaseDC(0, hdc)
    return color

def get_win_px(x=0, y=0, name="Device Manager"):
    hwnd = win32gui.FindWindow(None, name)  # warning no error handling
    hdc = win32gui.GetWindowDC(hwnd)
    color = win32gui.GetPixel(hdc, x, y)
    win32gui.ReleaseDC(0, hdc)
    return color

def press_win32(key_code=0x20):
    win32api.keybd_event(key_code, 0, 0, 0)
    win32api.keybd_event(key_code, 0, win32con.KEYEVENTF_KEYUP, 0)

def dpress_win32(key_code=0x20):
    """Include a delay between key down and key up events"""
    win32api.keybd_event(key_code, 0, 0, 0)
    time.sleep(0.05)
    win32api.keybd_event(key_code, 0, win32con.KEYEVENTF_KEYUP, 0)

def pressed_win32(key_code=0x51):  # 0x51 == q
    return win32api.GetAsyncKeyState(key_code) & 0x8000

def get_px_pya(x=0, y=0):
    return pyautogui.pixel(x, y)  # [0]  # (R, G, B)

def press_pya(key="space"):
    pyautogui.press(key)

def pressed_kbd(key="q"):
    return keyboard.is_pressed("q")

def detect_and_press(x=0, y=0):
    try:
        hdc = ctypes.windll.user32.GetDC(0)
        while True:
            if ctypes.windll.gdi32.GetPixel(hdc, x, y) & 0xFF > 150:  # compare red value
                win32api.keybd_event(0x20, 0, 0, 0)
                win32api.keybd_event(0x20, 0, win32con.KEYEVENTF_KEYUP, 0)
    except KeyboardInterrupt:
        return
    finally:
        ctypes.windll.user32.ReleaseDC(0, hdc)

if __name__ == "__main__":
    import timeit

    loops = 100  # how many times to repeat the function call
    multiplier = 1_000 / loops  # convert to ms
    for function in get_px_ctypes, get_px_win32, get_px_pya, get_win_px, press_win32, press_pya, dpress_win32, pressed_win32, pressed_kbd:
        fn = function.__name__
        print(f"{fn}:\t{timeit.timeit(f"{fn}()", setup=f"from __main__ import {fn}", number=loops)*multiplier:8,.3f} ms")

Without having the minigame oursleves, it's hard to tell if proposed solutions will eventually work. Anyway, here is something to explore.

pyautogui is slow

As you can see in the documentation, a call to pyautogui.pixel() is actually just a wrapper. It's hiding the hideous fact that even though you are specifying the pixel of interest, the code takes a screenshot of the whole screen first. According to the documentation, this takes roughly 100ms, so it matches your results.

To avoid this, you can define a region of interest (see here):

REGION = (2400, 690, 1, 85)  # x, y, width, height covering both pixels

# Pixel coordinates relative to the region
PIXEL_1_REL = (0, 0)  # 2400, 690
PIXEL_2_REL = (0, 71)  # 2400, 761

while not keyboard.is_pressed('q'):  # This is considered more elegant than `==False`
    screenshot = pyautogui.screenshot(region=REGION)
    
    # Convert to numpy array for fast pixel access
    img_array = np.array(screenshot)
    
    # Check both pixels
    pixel1_r = img_array[PIXEL_1_REL[1], PIXEL_1_REL[0], 0]
    pixel2_r = img_array[PIXEL_2_REL[1], PIXEL_2_REL[0], 0]
    
    if pixel1_r >= 150 or pixel2_r >= 150:
        press_spacebar_fast()
    
    time.sleep(0.001)

Please note the final line, which adds a little delay before restarting the loop. You should avoid looping infinitely through a loop with no pause, as it could cause 100% usage of CPU.

Additionally, if, as you say in a comment, having time.sleep() in your press_spacebar() function doesn't change anything, you should remove it.

It’s easy to get data into the GPU, but harder to get it out

Capturing the screen image is very slow because the CPU needs to perform a full rendering process to compose the screen image.

The solution is to capture the image for the window instead of the screen.(On my computer, the speed is 7ms vs 0.2ms, using C)

Code: (using C and winapi)

HWND hwnd = FindWindowW(ClassName,WindowName);
while (true) {
    HDC hdc = GetDC(hwnd);
    COLORREF color = GetPixel(hdc, x, y);
    ReleaseDC(hwnd, hdc);
    int red = GetRValue(color);
    int green = GetGValue(color);
    int blue = GetBValue(color);
    Sleep(1);
}

Unfortunately, I don't know how to translate this into Python, but I'm sure AI can help you with this step.

If you need to retrieve pixels from multiple points simultaneously, you should use BitBlt instead of GetPixel; otherwise, you'll waste significant performance. Of course, this will be slightly more complex.

If you can't get the window image by using GetPixel/BitBlt (the pixels set by SetPixel won't be displayed on the screen), the simple solution is to disable hardware acceleration or dGPU. As for a more complex solution... I personally use WindowsGraphicsCapture in C++, but I don't know what to use in Python.