One plus 12R

Hi, I am a OnePlus 12R user. My phone is 1 year and 3 months old, and the battery health is 96%. Currently, the device is running on the OS 16 April update. I am facing heating issues and performance drops while gaming. I think the screen-on time (SOT) is okay. I am a heavy user and usually play games like BGMI and eFootball. While playing, the temperature rises to around 40–44°C within 15 minutes. I am planning to downgrade, but I don’t know which OS version provides the best performance and battery backup. I don’t care about features like AI. Please suggest the best version for my 12R and share your thoughts and experience with this device. Also, let me know how to avoid thermal throttling, if it is possible, so I can utilize the system’s maximum performance. I have also heard that some devices got bricked while downgrading, so I am a bit concerned about that.