CPU constantly at high temperatures even when idling
I bought my macbook around 3 years ago and I noticed from the day I started using it that the fans were kicking in pretty often even when I wasn't doing any heavy or intense task. I brought it to an Apple reseller that checked it and said it was fine, so I went over it...
It's been a good amount of months now, probably more than 6, that the temperatures are clearly not right for my usage.
I was constantly at more than 50-55 degrees celsius, even when I had nothing opened. One clear example of the thermal issues that I'm encountering was when I had 4 firefox tabs opened and nothing else, literally nothing not even in the background (checked activity monitor), and the temperatures were bouncing between 90-100 degrees and the whole OS was lagging, and no they weren't weird browser tabs, I opened them on my friend pc since my mac was lagging as hell and they were totally normal web pages, nothing fancy.
Seeing some other forum posts and youtube videos, I decided to replace my battery and thermal paste. I used my mac constantly to write code so I did use it for pretty heavy tasks very often, the battery had around 900 cycles and I though that with my intense usage the thermal paste needed to be replaced.
Here is the thermal paste before replacement
I bought the kits and replaced both, but it changed literally nothing. The temperatures are still very high, >50° when idling with no apps opened at all, easily at 95-100° with a standard code IDE opened, and from 60 to 75 with some simple safari tabs and Spotify.
I also ran benchmarks before and after the replacement and it seems that it is worse now? Before I was getting 4160 points and now I'm getting 4114 (with multicore), so the thermal paste wasn't the issue?
The only thing that I could have done wrong is putting an excessive amount of thermal paste on, but I don't think that is the issue, I'll attach a picture anyway just to make sure I didn't mess that up
At this point I have no idea what the 'cause might be, I'll leave here a report of the temperatures while having some everyday apps opened in the background: Whatsapp, Todoist, Safari, and Spotify
I just wanna understand what the issue is 'cause it's so frustrating. My friend has the previous 2020 model and he runs dozens of apps together while still staying under 50° degrees and it just doesn't make sense.
Edit: I forgot to mention that I wiped the OS twice to make sure that it's not a software issue