Fenix 6s Sapphire: GPS troubles

This is the 4th run I've tracked so far and I run 275m track in laps, with some parts of the track under a tree cover.

ASICS Runkeeper app + Samsung GS 20+ tracks well but the Fenix 6s so far has failed pretty badly with 10-15% undercounting of distance/ pace.

Questions:

1. Does GPS/ Glonass/ Galileo accuracy improve with usage like it used to with my FR 310xt? (had terrible GPS in the beginning but improved over weeks of usage)

2. Is the Running Dynamics Pod causing accuracy issues? 

3. Can I get satellite constellation information on the Fenix 6s Sapphire? FR 310xt had nice graphs, bars to show you satellite data - # of sats, # sats locked, metres of accuracy etc.)

4. Accuracy with GPS + Glonass has been bad, GPS + Galileo has been mixed. Is GPS only advisable?

Other details: GPS 5.30, Software 19.20, CPE: Current | I had synced with Garmin Connect on my phone the previous night