You might be interested in the Oura ring then. I can't recommend it, because I haven't tried it. But sounds like the kind of thing you're talking about.
They certainly can be a deep and expensive thing, lol
But it can also be very affordable! Can get a perfectly great mechanical for around $100!
(Although, now that Seiko has abandoned that price level and prices on everything have gone up in general, $150-$200 is perhaps a more realistic starting point. Still a lot of "new old stock" Seikos at that $100ish price though if you look...)
While I realize these dollar amounts are not affordable to everybody, I have noticed that many people who scoff at these prices happily spend hundreds or thousands per year on their hobbies and entertainment....
All prices in Canadian dollars. Each of these has a place in horology; meaning; or use for me. The Wilk is a custom piece; there will never be one that is the same. The Casio is for "geek cred". The Orit is for health monitoring. I normally wear two watches. Both the Seiko 5 and the Amphibia have cemented their place in watch history.
They make me happy... these watches are, in general, not looked down upon by "watch snobs".
This story (making an Apple watch into a mechanical) makes me smile... now I want one!
Note that the Seiko 5 SNGZ09K1 is now $281 (Canadian) from Amazon. But the Vostok is $148 now (again, from Amazon).