1a) Yes TicWatch 3 Pro works with HR/HRV or SPO2 (not both at the same time)… I’m using the watch every day fro tracking and this is why I was able to find the sensors and implement it.. otherwise there are no standard sensors for SPO2 and SDNN on Android… I can just assume that some other Wear OS watches also have those sensors on the same address.. but I do not know.. I’m eagerly waiting for some user with another Wear OS device which SPO2 to report if it is working… and if it is not I can determine the address from the log and make it working for the next release of the Wear OS Sleep as Android app..
2a) Yes, exactly.. but I would need feedback and logs..
1b) We have implemented SPO2 and HRV on Garmin watches if my colleague @jiri-urbandroid can confirm.. but so far we have very little feedback on how is this working, we cannot really test it as we do not have a SPO2 enabled watch at the moment..
2b) The OEM of the watch must have implemented the sensor in the standard Senser interface.. I do not think you can learn this from the device specs .. we need to to test it on a real device.. BTW are there any other Wear OS watches with SPO2? I did not yet made this research..
Many thanks!