Elevation (alitude) and Solar issues on Fenix6X Pro Solar

First problem: Elevation (Altitude)

With v16.7 and now with v17.72 I still have the same issues with the Altitude. Big differences with my watch in comparising with several sites.
Also I have too soon accomplished my climbing steps on a day.

I have resetted my watch to Factory settings, but nothing helps. Also calibrating won't help. 

Second problem: Solar charging is not working properly since March

Image in March (winter period):

Image from a 22km run in the sun with 26 degrees:

I think there are some hardware issues with my watch. What can I do? Have anyone solutions or same habits? How to contact Garmin for technical support?

Thanks a lot!