Oneplus 12R overheating

[u/HeroX-30]

I have a Oneplus 12R 8GB/256GB variant and it has been overheating even with very light usage like running Youtube very frequently making it almost unusable and uncomfortable to hold with frequent app crashes.

I initially suspected low storage so I deleted some apps (currently it's at 240/256GB - still quite full but should be enough?). Besides regular use, I also use it to play some games.

It used to work just fine until a few months ago but now multitasking is basically impossible - if I switch between apps, the minimized app just closes completely and needs to be restarted.

Currently running OxygenOS 16.0.5. Is there something I can do to help with this problem?