GPS lock status

There a five bar GPS signal strength gauge, like a phone signal gauge, as a data field. That's all, AFAIK.

The last Garmin wearable with this possibility was the Fenix 2. 

Thanks - found that data field. 

Yeah, that’s what I meant. No longer supported? Shame. 

That data field only available in activity though?

Correct.

Perhaps something here - https://apps.garmin.com/en-US/search?q=gps+data&device=&deviceLimit=&appType=&sort=&start=0&count=30

Aah, I just wish if Garmin release an update with GPS constellation status display like old Fenix series. We even have much better screens but no info...

This is another step backwards compared to older Garmin watches and the competition. An image of the satellites and their levels is an important information for the users. From a display point of view this can be no problem. The display with some bars is not a replacement, because it does not give any information about the number and the field strength and fix.