I am having the same problem with my S21 Ultra Snapdragon. Mine is going a step further, though. Sometimes I get the 1-2 second pauses then it resumes, but other times it is freezing for a few seconds then crashing the phone and it reboots. After these full crashes, I have to re-download and re-install the full 8gb game. I was really not expecting this on a brand new device. I never had this problem with the Note 10+ 5G I upgraded from.
I've even tried lowering FPS to 20 and setting quality at medium and 3D resolution at 50%. It's gotten so bad after the last update that it's crashing before I even get to the matchmaking island.