Dell G7 7588 Overheating Gpu and Cpu throttling and downclocking Mhz.

Hello, I would like to report a problem that I have been having for a while and was unable to resolve. I have a notebook model dell g7 7588, the problem is that in the last year he started experiencing heating problems generating a lot of lag. I used to use it on Dell Power Manager in Optimized mode, but the gpu hits 77 degrees and drops the clock to 139 mhz, leaving any game at 20 fps steady, so I started using the ultra-performance mode, the gpu clock was normal, but the cpu clock started to drop a lot and the games started to get much lower fps than I normally played before all this happened. I've tried everything, updated all drivers, bios everything but I can't solve it at all. The point is that when it reaches a temperature, the clocks simply go down automatically and the temperature is not too high. I suspect it was after some bios update, but I can't downgrade. I really hope you have a solution, as I paid dearly for this laptop and it is giving me a lot of problems, making it impossible for me to play several games, which I played some time ago.