My s22 shuts off randomly. If I restart it does again in less than a minute. Doesn't feel particularly warm so I doubt it's overheating. If I give it an hour or more it's back to normal.
My first guess would be battery issues. (Of course, having battery issues myself might color my thoughts on this.) Check your diagnostics, and if all is well, allow your battery to drain almost all the way. Then charge it up and see if that fixes it. You also might think about using the adaptive charging mode. It's supposed to be better for the life of the battery. But don't get me started on Samsung battery life...
If the phone continues to power off, it is recommended to have the phone evaluated at an authorized service center. You can use the following link to find a list of service centers in the U.S. that can do the repair: http://www.samsung.com/us/support/service/location or by contacting customer support at 1-800-726-7864.
