It’s perhaps not a fully fledged fitness tracker, and it’s certainly not a smartwatch - but my favorite health tracking device has turned out to be my Oura ring.
I used it alongside my Apple Watch for quite a while, but I’ve found that the Oura ring gives me plenty of insight on my sleep, recovery and (more limited) activity. And the form factor is just awesome! I don’t even notice I’m wearing it, and I only charge it every 5 days or so.
I’ve stopped wearing the Apple Watch altogether now, and I find it freeing not to have all those notifications available on my wrist, while still having the health tracking I want from the Oura. Obviously it’s not a good fit for someone who does want the other features of a smartwatch, but solely as a health tracker I really like it.
As a gaming mom myself, I’d second the Steamdeck recommendations. I love mine! Best thing I have bought in years honestly.
I can play in the living room, while hanging out with the rest of the family, and I take it with me on work trips as well. I don’t have Valheim on it, but I do have No Man’s Sky and it works well. I’m currently playing Baldur’s Gate 3 on the deck - there are so many great options.