Samsung Health is useless

I had a previous complaints about Blood Pressure measurement via my watch 7 is useless. Even for simple measurement like oxygen level, I constantly get values around 95%, but I never get anything below 99% from a real oxygen reader.

So what is actually trustworthy on galaxy watch? I seriously doubt sleep apnea because it's dependent on the oxygen readout. The only things I can trust is step and pulse.

For people who has Apple watch, is it also that bad?