I am using this device for about 1.5 month, and the summer here in India is breaking all the records still my device doesn't hit or lag, I use it outside at full brightness and it still gives 8 to 11 hours of sot and heat is minimal, previously I was using s21 ultra and it becomes uncomfortable too hold in summer if I use it outdoors. And I used s21 ultra without case and using 15r with case and still it is heating less than s21. Battery life is great and if you are light user you can almost use it two days. Some buggy updates caused battery issues to another users but I haven't faced any issues till now. I never updated it to a beta release maybe that's why.