VSCode/Pylance highlights "Import could not be resolved" after moving files from a subfolder to the root

I’m working on a Python project on Windows 11 using VSCode.
I recently reorganized my project by moving all files from a subfolder to the root folder so that the code can be executed directly from the root.

Here is an example of the structure before I moved the files :

root_folder/
    sub_folder/
        package1/
            __init__.py  # empty
            script1.py
        package2/
            __init__.py  # empty
            script2.py
        main.py

And here is an example of the structure after I did :

root_folder/
    package1/
        __init__.py  # empty
        script1.py
    package2/
        __init__.py  # empty
        script2.py
    main.py

Before the reorganization, an import in 'script1.py' was as follows :

from sub_folder.package2.script2 import example_func

After the reorganization, I changed it to :

from root_folder.package2.script2 import example_func

My problem is that although the code runs correctly when I execute :

python -m root_folder.main

In VSCode, the import is highlighted in yellow with the warning :

Import "root_folder.package2.script2" could not be resolved

I’m new to programming. All questions I found talked about a specific case or about importing a library instead of self-made code.
The issue seems related to how VSCode/Pylance analyzes paths. So how can I make it so that it correctly recognizes imports after I moved my files to the root folder ?