Can I connect an Apple Watch to my iPhone without syncing activity data? Or is there another way to roll back Activity data? First, the problem: I accidentally entered a 25-hour workout manually instead of a 1-hour workout (I entered &quot;yesterday at time X to today at time X+1&quot;, instead of &quot;…to yesterday at time X+1&quot;).  I deleted it immediately, but the damage was done.  This gave me thousands of unearned exercise minutes and has awarded me an unbeatable exercise record achievement, which are both really frustrating – I've been tracking my data for over a year now, and this really gets in the way of that.
Unfortunately, after talking to Apple Support for over an hour, I learned that there really isn't a way to undo this.  The exercise minutes haven't gone away, even though Apple Support said they were supposed to, and Apple Support said there's literally no way to remove achievements short of resetting my data completely.
Except!  The reason I'm in this pickle is that my Apple Watch actually basically died recently (or maybe not quite, some of the issue seems to be with the charger (that I've now replaced)) – it's barely charging (this might be cable-related), discharging quite rapidly, and basically isn't usable.  However, it might be usable enough to connect to my phone and unpair from it, which would create a backup with the old, pre-disaster activity data.  There's just one catch: as soon as I connect it to my phone, it's going to sync, importing the new data and breaking everything.  Apple Support wasn't sure if there was a way around this.
So that's my current situation.  I have my phone and a borrowed Apple Watch with the post-disaster, thousands-of-exercise-minutes Activity data, and my old Apple Watch with the pre-disaster good Activity data.  I want to import the data from my old Apple Watch and zap the data from the new Apple Watch.  How can I do this?
I'm also interested in other ways to solve this same problem – I'm under no illusions that I've thought about this completely enough to totally explore the problem space.  But this is the best idea I've had.

In short: Can I (1) connect an Apple Watch to my iPhone (2) without syncing activity data, then (3) unpair it to create a backup, and (4) restore another Watch from that backup, thereby (5) wiping out the past few days of activity data?  Or is there a better way?

Product versions:

Phone: iPhone 8+, iOS 13.5.1
Old watch: Apple Watch Series 4, 44m, watchOS 6.2.8
New watch: Apple Watch Series 5, 40m, watchOS 6.1


I also asked this question on Reddit in /r/applehelp.
So - as a direct answer to your question - no, unfortunately it doesn't appear possible to do what you're asking.
Now for a longer, more descriptive answer. After carrying out some research and performing some of my own tests, it unfortunatley doesn't appear that it's possible to simply remove a single exercise whilst also deleting the corresponding award earned from it; removing the exercise from within the Health app leaves the award which can, as you mentioned, still be found within the Activity app. The following threads posted to the Apple Discussions forum were posted by users who also had a similar problem - confirming the above:
https://discussions.apple.com/thread/8257414
https://discussions.apple.com/thread/250261634
https://discussions.apple.com/thread/250009083
In addition to this, it also doesn't appear possible to use the backup of an Apple Watch to simply replace the Activity data/rewards on the Watch's paired iPhone; that said, I'm not 100% sure whether the Watch backup itself actually includes any Activity data itself, or whether this is only retained on your iPhone. It appears that the only way to resolve this is to reset your Health data - which is far from ideal, but appears to be the only resolution at this time.