User Activity

When changing from 5g to 4g or 4g to 5g and wifi to mobile data my internet is not working. It works only when restarting my phone.Kindly let me know the solution.
I'm using s21 fe exynos processor, i can't even use Google map for 20mins continuously and can't play high graphics games for 5 minEvenafter done reset my phonePhone getting toooo hot 掠
Why im always getting this warning in my phone ?
Fingerprint missing can't unlock my device sometimes
Whenever i restart my mobile/sim my mobile network changed into 5g even on battery saver mode ., please fix Asap, it draining my battery very fast.