SQLite database not being created in Flask instance folder despite db.create_all()

I have a Flask application with SQLAlchemy that was working fine until now. Suddenly, while the instance folder is being created, the database file isn't. I tried db.create_all() via shell, it works fine.

Error:

OperationalError

sqlalchemy.exc.OperationalError: (sqlite3.OperationalError) no such table: user
\[SQL: SELECT user.id AS user_id, user.username AS user_username, user.name AS user_name, user.email AS user_email, user.password AS user_password
FROM user
WHERE user.email = ?
LIMIT ? OFFSET ?\]
\[parameters: ('[email protected]', 1, 0)\]

Project Structure:

v1/
    app/
        __init__.py
        models.py
        routes.py
        instance/    # Created but empty
    config.py
    run.py

My code:

app/__init__.py:

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from config import DevelopmentConfig

app = Flask(__name__)
app.config.from_object(DevelopmentConfig)
db = SQLAlchemy(app)

app.app_context().push()

from app import routes
from app.models import User

config.py:

class Config:
    SQLALCHEMY_DATABASE_URI = 'sqlite:///quizmaster.db'
    SQLALCHEMY_TRACK_MODIFICATIONS = False

class DevelopmentConfig(Config):
    DEBUG = True
    SECRET_KEY = 'super-secret-key'

models.py:

from app import db

class User(db.Model):
    __tablename__ = 'user'
    id = db.Column(db.Integer, primary_key=True, autoincrement=True)
    username = db.Column(db.String(15), unique=True, nullable=False)
    name = db.Column(db.String(80), nullable=False)
    email = db.Column(db.String(120), unique=True, nullable=False)
    password = db.Column(db.String(80), nullable=False)

run.py:

from app import app, db
from app.models import User
from sqlalchemy import or_

if __name__ == '__main__':
    db.create_all()
    # Create admin user if not exists
    admin_exists = User.query.filter(
        or_(
            User.username == 'admin',
            User.email == '[email protected]'
        )
    ).first()
    if not admin_exists:
        admin = User(
            id=0,
            username='admin',
            name='admin',
            email='[email protected]',
            password='admin123'
        )
        db.session.add(admin)
        db.session.commit()

    app.run(debug=True)

What's strange is that this code was working fine until now. If i run this now, only the instance folder gets created, the database was not created. I tried deleting the instance folder and made it recreate, still same issue.