Anecdotally, I have come to two conclusions regarding gps in SFOS.
First, having a source of correct time seems crucial, so mobile network needs to be enabled. There may be other shenanigans going on between modem and gps. (WiFi seems worse, but I lack data to support my impression.) It’s often ok to turn off mobile network once GPSInfo reports a solid fix.
Second, the defunct MLS seems to make things worse. Again, my testing is lacking, but I noticed a pattern where I don’t get a gps fix once GPSInfo reports a position with a multi-kilometer accuracy and no satellites available. This hasn’t happened since I removed the MLS packages and changed settings for Location