There are several options, each with their own pros and cons.
Qt [1]
The main codebase is C++, but bindings are available for Python and several other languages. I have developed and shipped multiple cross-platorm applications using Qt, using both C++ and Python. Documentation and source code examples are readily available.
JUCE [2]
Another C++ framework, with Python bindings. The focus is on music and audio apps, but a cross-platform GUI framework is also part of the library.
Blazor Desktop [3]
I have developed C# web applications using Blazor and WASM and moved them to the desktop easily. Using C# and the Dotnet ecosystem is really interesing and worth looking at.
Flutter for Desktop [4]
Still in beta, but has the support of Google, for better or worse.
JavaFX [5]
A Java cross-platform still under active development. I think it is pretty nice if you like Java.
Red [6]
Let's add an outsider just to keep things interesting!
This github site seems somewhat current about other Electron alternatives as well. [7]
Good luck! You will find there are lots of alternatives out there.
[1] https://www.qt.io/
[2] https://juce.com/
[3] https://visualstudiomagazine.com/articles/2021/02
/17/net-6-preview-1.aspx
[4] https://flutter.dev/desktop
[5] https://openjfx.io/
[6] https://www.red-lang.org/p/about.html
[7] https://github.com/sudhakar3697/electron-alternatives