You can install QtCreator or use command line pyuic6 -o main.py main.ui
How do I download QtDesigner for PyQt6? If there's no QtDesigner for PyQt6, I can also use QtDesigner of PyQt5, but how do I convert this .ui file to .py file which uses PyQt6 library instead of PyQt5?
Downloading QtDesigner for PyQt6 and converting .ui file to .py file with pyuic6