You can contain your native react creations in electron if you really don't want to go the native GUI kits route.

For all the shit that Electron gets, it is reliably cross-platform with relatively little effort.

I have looked extensively and unfortunately haven’t been able to find anything of the kind. Closest you would get is the Flutter framework which supports web. But that’s not Python.

You can use python with Electron ... with all that Electron implies.

There's a web toolkit for enaml. https://github.com/codelv/enaml-web