I tried a lot of places and nobody could actually solve my problem so i am explaning it the best i can, if you don't want to read everything skip to the second paragraph (still a lot to read lol)

I got my acer nitro an515-43-r4c3 (with a Ryzen 7 3750h and a Geforce 1650) on the very end of 2020, never had any problems with it for a long time actually, until the middle/end of 2021, when my computer started to reach high temperatures and deal with a lot of performance problems. To be honest, before it started, i never needed to make any configs in my pc for playing, I didn't use to know even what NVIDIA control panel was. After that, the fps drops and freezings on my pc started to get usual, more often on high requirment games, but then it started to happen to the most simple games too, overwatch 1 or valorant, both on low configs, as example. I thought i had a RAM problem, because the nitro's version that i have deals with the 2,1gb RAM dedicated to the integrated graphics, so i bought another 8gb module which is almost the same as the one that comes with it. My problem was "solved" for some time, until it started to happen again and, since then, it just got worse. Believe me i tried everything possible inside the PC, all the things with Windows optmization, changing configs on NVIDIA control panel, etc, i mean everything that was recommended in this community from people with similiar problems, even so nothing worked for me.

I started to notice that the freezings, stuttering and fps drops were always followed by a temperature peak, everytime that they happened i did a quick Alt+tab to nitrosense or task manager and noticed the temperature going around 92 to 96 °C, so i learned about thermal throttling and that it is normal to happen on this temperature levels. So i really believe that i have a overheat problem and i also tried "everything possible", like setting the coolers preset to maximum via nitrosense, lifting the back of my laptop a little bit, even the thing with changing the power profile on windows or setting a maximum temperature on ryzen controller (both of the methods reduce my cpu's speed by half and the games get almost unplayable). Recently I tried to send it to maintance, because my keyboard keys started to pop off one by one so i needed a keyboard change, also i asked them to do a complete clean and repaste it. After a while the shop said that the keyboard part i needed was difficult to find and that they would have to change the laptop's complete bottom part and that it was ok if i disagreed with that, the price was a lot more than the previous one so i didn't accept it, but even so i still asked for the repaste and they said that it was probably not the problem because it was still "wet", so i didnt need a repaste (even if i never did since i bought the nitro). Well after two months or more, in case nowadays, it is getting in a point that i can't play almost any game without a fan on my side turned in the computers direction, the temperatures on every game get really high (around 88 or 89 with 93/94 peaks) and while playing most of it my gpu's usage is below 20 or 30 percent, something that i don't understand, because i always update my drivers and i configured every game to run with nvidia's high perfomance card on the panel and even on windows, but it seems to use more of my cpu (always close to 100% usage) and integrated gpu instead of it. I honestly don't know what to do, my product is not under warranty anymore and i think the problem may be the thermal paste because i never changed it, but im not sure because of the maintance shop statement, if somebody could help me i would be really thankful.

I can provide any configs, specs, reports, task manager print, or anything related just ask if it is needed.