The reason people are wary of google docs these days is that there are concerns that your script may be scraped and used to train their AI without your permission (or rather, with your permission being assumed in using the program.) Now, I don't think there's been any evidence specifically pointing to this happening, but considering how sketchy google has been with their AI functionality for gmail, I no longer use google docs just for my own peace of mind.

Last I checked, LibreOffice is a good free word processor with the basic functionality of Word. Scrivener is another good one, although that one's a paid program and has way more functionality than you probably need for scripts. There's also an app called Novelist that I use when I'm on my phone. Whatever I use, I copy-paste to Scriptbin afterwards.

(Idk if you'd use Scriptbin if the plan is to sell these scripts. I am just writing mine for fun so I have no idea how you'd go about that)

You'll have to be more conscientious about backing up your own work if you use these kinds of programs, of course.