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Cross platform Python app development
(lemmy.ml)
If you referring to GUIs:
GTK for Python: https://www.gtk.org/docs/language-bindings/python/
Qt for Python: https://www.qt.io/qt-for-python
If you mean making an executable that can run without separately installing a Python interpreter or PyPi dependencies, there are Python packagers like Pyinstaller: https://pyinstaller.readthedocs.io/en/stable/
I had been scrolling Mastodon timeline and found Flet - a framework for writing Flutter apps in Python.
Though I haven't tried it yet, it could be interesting and useful for you.
Links:
News and discussions about the programming language Python