 Health data is now securely synced via iCloud. So as long as you log into your same iCloud account, then your health data will sync back down to your phone and your watch and all of that stuff. Yeah, I did this a couple of years ago when I clean installed. I think it was my 12 mini or 13 mini. I can't remember which one I did that with, but the clean install was great and I have my health history all the way back to whenever that was, to whenever health started for me.