But use type annotations everywhere and make sure your code is always checker clean (with checkin or PR CI hooks). And don't turn off any lint checks through laziness, e.g. docstring checks. Even for a solo dev it's always worth having everything typed, checker clean, and docstrings (even if they only effectively say "this thing really is what you'd assume"). It all saves time and effort in the long and even medium term.

I've worked on serious large scale Python projects and frankly it's been very pleasant and productive, but only with the above conditions.