Hi, I got an used series 6 3 weeks ago and unfortunately discovered I couldn’t pair it with my iphone (SE3) unless I updated the phone to ios 17. I had the same error message you got even though the watch had watchos 9 and the phone had ios 16, both of which are compatible. I was forced to update to make it pair.

Possibly, try to contact apple support to check if there’s any workaround?

Could you please share a link to the Workout app because I’d like to check it out but can’t seem to find anything named simply “Workout” in the appstore

Yes! I adore the Snoopy watchface! In fact, bought my (gently loved;) Nike 6 just to get Snoopy, even though I had decided previously to wait for apple to offer a watch version with good battery life…