> After the code has stabilized I can probably go back to write type hints [...] but I'm not sure that this would provide very much value.

I think most developers who revisit their projects 6+ months later would disagree with the second part of this statement.

My typical flow for "quick scripts" is:

on first pass I'll add basic type hints (typing ":str" after a func param takes .2 seconds)

for more complex data structures (think a json response from an api), dict (or typing.Dict) work fine

if you want a Python project to be maintainable, type hints are a requirement imho.