I'd hit up a garmin then or check out Superset Health. One app to show strain, recovery and sleep much like whoop https://www.supersethealth.com/?ref_id=EJ58S0ZTV
Shpeegz3
Get the s7 and sign up for Superset beta https://www.supersethealth.com/?ref_id=EJ58S0ZTV and you'll have everything garmin/whoop does and more.
I'm struggling with this very thing right now.
I have an AW8 and I just got an Epix Pro 2. Apple watch is thinner and lighter which makes it great to wear and sleep with. But battery life is terrible compared to my 42mm epix. AW has some modern conveniences that are nice but not deal breakers for me.
Sleep: Garmin is garbage. Deep and REM are tough, I get that but garmin can't even get awake times right. If I wake up at 3am and am awake for an hour my AW nails that but garmin thinks I'm in rem or light sleep. Garmin also will still think I'm sleeping even after I turn on sleep mode and am out having coffee on the couch. AW never does this. Considering garmin gives a "score" for quality of sleep and it can't accurately measure that is a bit questionable. That score goes in to training readiness so it really makes me question it's accuracy there.
AW seems spot on in sleep.
Stress: This is actually really nice on garmin and seems very accurate. Apple does not have this natively but third party apps can bring this somewhat.
Garmin looks so much better though. Looks like a normal watch and I made a custom Starfield watchface which I love. AW can't even compare in that. Every AW face I have I always wish I could tweak or take an element from another face and use it but youre stuck with apples way or the highway.
If you go apple check out Superset Health. Launches early next year and is in beta now. https://www.supersethealth.com/?ref_id=EJ58S0ZTV
For a little better AW experience check out Superset. Beta signups now and should be launching in a month or two https://www.supersethealth.com/?ref_id=EJ58S0ZTV