Lending device to test vo2max without it screwing up your stats

Ok, I have already asked this questions a few years back without a good answer.

I own 2 Garmin devices (f7x as and epix 2).

Yesterday my 11 year old son wanted to run with one of my watches.

I remembered it screwing up my stats for 4 weeks since he is in much better shape...

So I reset the epix to original mode (full swipe).

He does his run...gets his stats (gps, time, hr...).

Now, to reuse the watch I would have to reset it again and resync it to connect via physio tru up.

Is there a way other than this to lend the watch (different profil like a computer?).

Thanks