S22 series does not have MST. The S21 didn't have MST in the US either. I'm pretty sure it was the S9 or S10 series that was the last North American model that came with MST. I can't believe Samsung did away with that feature, it was actually the driving factor in me buying my first Samsung smartphone, Galaxy S8+. It's a fantastic feature that was uniquely Samsung and was extremely handy. I can't think of a good reason why they dropped the feature but alas it's gone.
I understand that the patent expired or the contract with the originators. Maybe the originators wanted more money or something but...MST was the BEST method of payment, that's why I keep my watch S3 Frontier, looks great and for the MST.
I had the S3 Frontier for the longest time and for the same reason but it eventually just became too sluggish and slow to enjoy using. I just upgraded to the Galaxy Watch 4 classic a few months ago when I bought my S22 Ultra and despite having no MST, it's night+day how much more snappier and usable the Watch 4 is. I actually refuse to throw away my old S9+ because of the MST, I keep it in my car just in case one day I forget my wallet I can use Samsung pay+MST with my S9+.