Looks like the previous thread was locked, but I wanted to share my findings.
First of all, let’s acknowledge our watch is outdated. I still love mine though and don’t wanna buy a newer version yet.
Anyways, I fly everyday so I get to mess with it. It seems that if you go into the settings>apps>fly>altimeter, and use GPS instead of baro, auto detect at 500 fpm works.
Also had luck with turning off auto calibrate in settings>altimeter.
As far as flying commercially, keep in mind the cabin pressure is reduced before take off, at a variable rate. At cruise it’s usually 8psi replicating 8,000msl. So of course your watches baro will be confused.
I just don’t like how my watch will auto end then auto start every touch n go. Working on that. I love the watch and the app, keeps me active on the ground too. 33 day streak!
Cheers
-CPL/CFI/A&P