Best wearables for sleep, Heart, O2



I have just started using SAA. What are the best (best capture) wearables for Sleep, Heart, breathcount & Oxygen in blood capture, that integrate with SAA?

Know that these things are not medical grade, but want ones that are nearest. Cost is not a problem, as sleep & related problems are a big issue in my life.

And I am also open to using more than one wearable, to capture all things at their best quality.

BTW, I use oneplus 5, Android/OxygenOS v. 9.

Thanks to all giving pointers.