There are guides to disabling OnStar effectively which should assuage those concerns. Well, for the 23 and older models. Not sure about the new stuff.
A quick terminator on the cellular antenna makes it receive no cell signal - the other features that don't rely on cellular all continue working.
Agreed. I don't have an account, I used to look them up on archive.today but since that has its own... Baggage I just settle for not reading the rest lol.