I just started looking at HRV recently too, but haven't yet started tracking it. I had been reading about the Whoop device (you have to pay a monthly subscription, I was thinking of just getting the minimum 6 months to try out) and the Biostrap, that someone I know is testing and recommended.
I also looked at the Emfit online - and it looks awesome. You put it under your mattress, and it tracks your sleep, plus HRV and some other things I think.
I really appreciate the heads up on Welltory, I'm looking at them now! Very cool, looks like it might be an easier way to get started.
I guess my question would be - what do you do with the measurements? If they just make me stressed (because they're bad!) - that won't be helpful.
I recently trying the "Snore Labs" app - which records you if you snore. I didn't think I snored, but am trying to improve my sleep - and it was so awful! I mean, the app is fantastic, but the recordings of me snoring at night - literally wanted to make me cry, and now I'm struggling to sleep! (On the positive note, it's helping me feel more motivated to clean up my diet and lose weight!)
I don't know... but Welltory looks really interesting, and it's nice that you don't need to buy/wear any extra gear!