mine to, unfortunately no one in garmin have answered to me until know. after 20.50 update my watch did not work and my watch have frozen since 1 month ago. 

perhaps our duty was to pay 800$ to Garmin . shame...

Is there any warranty process? I thin my is for sure out after two years.
Do someone knows how can I do all these stuff in Ukraine? 

They have issued a 20.60 version apparently to solve this specific issue, you find the thread at top of the Fenix 6 forum, so it is an acknowledged issue, they should replace the watch. However, no idea how you do this in Ukraine especially now... Sorry for what's happening, BTW

I also have this triangle flashing and it won't work anymore

No, the computer is not compatible with the watch

Please see the "other" thread on this issue:
https://forums.garmin.com/outdoor-recreation/outdoor-recreation/f/fenix-6-series/288712/garmin-fenix-6-not-working-gets-stuck-during-startup-only-shows-the-garmin-arrow-sign-which-flashes-briefly-from-time-to-time

Basically, the 20.50 update killed many watches. Garmin is quietly acknowledging this, and replacing watches for free without complaint.  Hit up Garmin support and point out how the update killed your watch, and they should get you taken care of. 

Five repair clock