While this is primarily a Niantic issue, perhaps a gentle 'nudge' from Samsung might get their attention. All Samsung Galaxy Store versions of PoGo starting with 0.170.0 and subsequent updates 0.171.1 and 0.171.2 will freeze a few seconds after starting the game, from various Forum Threads around it seems to be just the S20 Ultra has this issue, i also have an S8+ and i even resurrected an old S7 Flat to test it and all updates are fine on them, luckily a forced update hasn't happened yet but when it comes looks like S20 Ultra players will be locked out, just to point out this also happens on the Google Play Store versions so ball is in Niantic's court.