Repair Apple Watch and iPhone without restoring from a backup of the iPhone

I have/had battery problems with my iPhone and was instructed by Apple to restore my phone from new. I was specifically told NOT to restore from a backup because Apple suspect the battery problem is linked to the software on my phone and restoring from a backup would mean the problem would persist.

However, as far as I can see the only way to pair my Apple Watch and iPhone is to erase the Watch and pair again.

This is simple enough but I have over 800 days of Activity data, awards, etc on my Watch and this is really important to me.

Please does anyone know how to pair the Watch and iPhone without losing the Activity app data and restoring the phone from the backup?

I suspect there is not a way to do this and am sincerely disappointed, if that proves to be the case. This would seem like an oversight by Apple.

Thanjs for for any help.