Slint

I really like Slint.

It has Python bindings, tho you wouldn’t know it from the docs as it’s brand new bindings.

However, it does WORK, and it works well.

Just look for python files in the examples and reference the slint docs (it uses its own UI lang for that stuff anyway).

I’m currently making an application in Python using Slint, and I really like it.

It also supports embedded systems, the web, and multiple languages, AND since it has its own UI lang, you can reuse parts of your UI code across different codebases

It seems to suit your use case.

Godot

Other than that, I second Godot.

HOWEVER

Godot’s GD Script is not Python but rather a Python-like language. (in fact, in some ways, I’m glad it’s not; there are things I prefer in GD Script).

This is important as you may want to use specific Python libraries which won’t work with Godot!

You can, however, use GD Native to bind C++ code and thus C++ libraries, so you’ll still be able to get done whatever you need to get done.

Iced

If you’re not tied to Python, then I recommend the Rust library Iced as it is a very intuitive system. I really enjoy working with it.

Although, that said, Slint has great support for Rust, so maybe I’d recommend Slint anyway if you were gonna change language.

Warning Against Legacy

Avoid GTK, Qt, and TK at all costs imo. Also WinForms if ur on Windows.

They’re old and crusty, and their APIs suck to use, even modern versions, and despite being aged, they’re buggy still, not robust “tried-and-true” methods.

It’s also hard to do dynamic stuff with them.

Just not well designed systems. Important, valuable to know bc they’re used all over, but not well designed

Immediate

I would also try ImGUI.

It’s meant more for gamedev UIs rather than Apps themselves (tho I’ve made a couple in it)

BUT

It’s a totally different way of doing UI called “Immediate” bc you program the elements in a big loop, rather than event driven.

It’s interesting and worth trying as a learning experience

React

And ofc, the Javascript/Electron world is huge and React is very popular with lots of tools. At least read up on it.