I've had a few problems with Strava on Galaxy Active 2 TIZEN as well. Sometimes it just doesn't find a gps lock.
I agree, it just has a feel of an app that's been "rushed out the door".
Exactly the same issue on Samsung S9 on android 9.
I thought my headphones had broken, I'm going back to mapmyrun till it's fixed.
Yes, the pace graphs on most other trackers are useful, Strava's is so bad I'm not sure why they bother.