Pixel Watch 5 & HIIT Style training?

It's time for a new smart watch. I adore my $25 Amazon special, but it no longer meets all of my needs. Since I prefer Google Fit over Samsung Fit, the pixel 5, which I can get super cheap through my cell plan with Xfinity, seems like a smart choice. Just one concern- how accurate is it in tracking metrics for high intensity interval training type exercise? I participate in 8 to 12 bungee fitness classes a week and my current watch, though it touts compatibility with Google fit, doesn't seem to be able to accurately report the metrics, I can do 2 1 hour classes back to back, and if my phone is in my pocket, I get my heart points. If it's in my locker or recording/live streaming the class? Nothing. It will show my steps after I sync my watch to my phone, but no heart points. It also tends to merge the steps it counts from my phone being in my pocket with what my watchs software reports, rendering the Fit fairly useless. The girls at the gym primarily seem to have Apple watches so they can't answer this other than to say they use the HIIT tracker on their watch and it works as it's supposed to. Any feedback appreciated