Will erasing Apple Watch in iCloud remotely wipe all data?

Ok so I have a wife against my knowledge looking thru my Apple Watch all summer long. I never use my Apple Watch. It’s always dead. It’s one of those watches that sort of just sits in a drawer always unused, untouched, and dead. But all summer long twice a week I get a notification on my cell phone, suggesting I update my Apple Watch. Clueless I hit ignore never doing anything about it. Just realized I think my wife is charging twice a week to just take a peak at any email or text message of mine as we are in the middle of a divorce. I currently haven’t set to erase the next time this week she slightly charges it to use it. But I want to catch her red handed to help my case as she has always done this to me, this spying stuff. Is there a way I can back up my Apple Watch before I erase it sometimes can go thru a back up to see what she has clicked on or opened this summer? Any help is great!