I see your points and I was going through pretty much all of them when deciding whether to go with typings or not (eventyally we did because I wanted to try it out and because pressure from Java people who found it odd that we don't care about types - actually we do, but instead of types we have strict naming conventions).

The point with sentry was that when making a decision in field you don't have much experience in, you look what other guys with resources are doing since they had these conversations already.

IMO in practice you will realize that in most cases typings are more of a burden than help - devs don't know typings and will spend a lot of time thinking how to annotate, making constant decisions whether to annotate/not annotate (aka incremental typing). That inconsistency drives me nuts - aka defeats the whole purpose - you do something right or don't do it at all right?

I see the point with documentation, yes it is nice to have, but more important like I said before is proper onboarding readme file and docs + willingness of other devs who are working on the codebase to handhold when necessary.