My forerunner charges whilst I am working at my desk, it's no biggie.Your Fenix 8 also takes like 3 hours to charge whereas an Apple Watch Ultra will charge from 30% to 80% in like 30 mins while you shower and will last another day or two.
Having said that I have preordered the watch ultra 3, hopefully it gets through a weekend, but in reality I'll probably just charge it overnight as I don't pay much attention to sleep scores. You know if you slept well or not.