Since Catalina, Always High CPU & Overheating

Hello,

despite googling like crazy and finding many people with similar issues, I couldn't find a solution and I'm getting pretty crazy.

I have a 2018 Macbook air (16GM Ram) which is literally always going for high CPU, being slow and overheating since I updated to Catalina (nothing changed now with BigSur).

I tried to focus on single applications (switching from one browser to the other, and try to stop using some of them) but I soon figured out that was not the problem, because the system gets crazy regardless what I'm using (it just needs to be 3 chrome/safari tabs or a two apps).

I went for these lists of fixes like reset SMC, PRAM, cleaning stuff and so on, but still no luck. And as you can imagine I'm a bit frustrated having a 2018 macbook and seeing people with way older systems working nicely.

If anyone would be willing to help I couldn't be happier and more thankful :)

Thank you!