Question GPU fan problem

Sep 18, 2020
So, here's the deal:
I was playing a game, when I started to notice some stuttering, and that it happened after 2 to 3 minutes of gameplay, and it would happen constantly after that, so I fired up MSI Afterburner to monitor what was happening, and I saw that my gpu temps were WAY up, like 100°C (212°F I think), so the gpu was thermal throttling. Then I looked into the gpu fan, and it was spinning a little, for a second or two, and then stop spinning, and spinning again over and over. I know gpu fans aren't supposed to run properly until a certain temperature threshold, but it didn't spin properly even in 100°C. I unplugged everything in my computer, cleaned everything and rebuilt my computer. Didn't fix the problem. I tried a live linux usb to see if it was a software problem, also didn't saw a difference. I tried manually setting the fan speed with a lot of softwares (MSI Afterburner, Speedfan, Argus Monitor) to 100% speed, and it didn't work as intended as well, the fan was going from 400rpm to 0rpm constantly, even when I setted the fan speed to 100%. I grabbed an old fan from my old computer and put it bellow the gpu and plugged it to the mobo pwm, and set that fan to the gpu temps, it is helping the gpu to stay under 80° in the same game, but I want to play properly without using this solution, so I was planning to replace my gpu, but I don't know if it is even the gpu.
I checked in HWMonitor and GPU-Z to see the voltage and the wattage to see if it was a PCIe or PSU problem.
in idle the PCIe voltage is 7-9ishV when I checked, but when I ran furmark it goes down to 1.5V(is this normal?)
The gpu wattage is 35ish idle to 68ish when in full load and the voltage is 0.675V idle to 0.881V max(checked in HWMonitor)
I am also using the latest drivers for my gpu, and I also updated my mobo bios a year ago(I don't think it has a new update)
I don't know exactly when the fan started doing this since my computer were in the floor(it is in top of my desk now), but I checked the temperatures in the start of this month, i guess and it was working properly, so it must be recent.
I have this computer for 2 to 3 years now, so no RMA.
I would like some tips as to what could be the cause, so I can know what hardware I must buy to solve this issue, or if I can fix my gpu fan

Here's the pc specs:
CPU: Intel core i3 7100
GPU: Asus Phoenix 1050ti 4GB
Motherboard: Gigabyte H110m gaming 3 LGA 1151
PSU: Corsair VS400 80plus white
RAM: 2X Corsair Vengeance lpx 4GB 2400mhz ddr4
I guess that is the specs you guys would need.

Sorry if I misspelled something, as english is my second language(I am brazilian), and thank you for sparing your time to help me.