These are exactly the issues I would have guessed you would run into when using Python in a spreadsheet. Python has really been promoted above its level of competence. It's not suitable for these things at all.

I would say Typescript is a more obvious choice, or potentially Dart. Maybe even something more obscure like Nim (though I have no experience of that).

I get that you want compatibility with Pandas, Numpy, etc. but you're going to pay for that with endless pain.