I've successfully built apps with Python and Qt (PyQt6 and PySide6 are both working fine). The overall file size of the resulting folder is about 60-80 MB on Windows, mostly due to all the Qt DLLs/plugins you'll need to ship. By manually deleting non-necessary DLLs, you might save maybe up to 20 MB. Just considering the file size, this might not a huge gain compared to Electron, I suppose?

However, keep in mind that desktop apps have the major disadvantage of figuring out distribution (separately for each platform!!), which includes the following two steps: 1) packaging the application in some format (e.g. an MSI installer for Windows and a Disk Image Bundle for macOS), and 2) distributing that package (including auto-updates). I have written a number of articles about this topic, see https://www.augmentedmind.de/2021/05/30/distributing-windows... and https://www.augmentedmind.de/2021/06/13/distributing-macos-a... . You get rid of all that if you just built a PWA or other kind of web app.

In addition, if you use Python, you also need to choose a "freezing" solution, such as PyInstaller (more details at https://www.augmentedmind.de/2021/05/16/distribute-python-ap... ).