Update from next activity:
I have been out for a running activity again following almost the same route as before. In the meantime, a firmware update has been released and I performed the update. Additionally, I have followed the advise from Suunto website’s FAQ and replies in this post: performing a soft reset on the watch and making sure I have synced the watch with the phone before the activity.
This time the GPS tracking was nearly spot on.
I will keep checking in the coming activities to see how this progresses. Thank you all for the inputs.