I have to say that I never really liked the fitness watches. I found them too distracting for my monkey brain. If I had an Apple watch or the Galaxy watch, I'm afraid it would drive me crazy with all the distractions it could cause me. Yes, I know I could turn off the text message alerts and all of the others, but just the fact that it could show my BP, and other items would be distracting enough.
For me, unfortunately, I wear a "smart watch"... it was the original smart watch. It tells time, and sometimes I wear one that even shows the date (an analog mechanical watch). To me, that is smart. The other side of it is I love watches and love to take them apart, clean them, and make them work again when broken... so for me, the only reason I might wear a fitness watch is when I work out, which unfortunately, because of beta blockers and other things, I don't do much of (I need to change that).
I did play around with a FitBit years ago, a Polar watch and I also had a Xiaomi Mi band. They were all nice, and did some things well, but again, too distracting.
I also bought a device that costs about $100 that can do your EKG. The problem is, with a Left Bundle Branch Block (LBBB), it doesn't tell me anything other than my EKG is abnormal. Granted, I can still see it and shoot it over to my cardiologist, so for $100, I guess that's okay.
I did really like the Polar watch. It was older, and I too had issues with the strap. Sometimes it would work, and others it didn't. I found that Xiaomi Mi band though always worked (no idea how accurate it was compared to the Polar watch though).
One thing I did recently get though was a bed that tracks a lot of your sleep info (avg heart rate, heart rate variability, etc). My heart rate variability is always very low compared to my wife (who doesn't have any heart conditions nor takes any heart meds). I don't know if the beta blockers or the LBBB might be causing that. I also don't know how accurate the variability is. I'm fairly certain the heart rate is fairly accurate as I've checked it against results from a Zio Patch and they were spot on. I didn't see the variability in the data from the Zio though.