I recently bacame an owner of Garmin Fenix 7 pro #824870, and since that day daily step goal has been stuck on 5117 steps whatever the trip I made. And yesterday I found how to fix this bug.

1. in the Garmin connect edit step goal;

2. turn off "Auto goal", ented random step amount and save;

3. restart your watch and Garmin connect;
4. turn on "Auto goal" and save.

...and the very next day my daily step goal started adjusting based on daily activity. I found this solution on Reddit, now it has to be stored on SN