I was using debloated driver so I reinstalled my drivers and its pretty much same... GPU still working at around 50%

Where can I check that? I guess it is 50% on all cores cuz temps are nearly same and clock speed too...

Its not pinned at 50% its around 50% (40-60%). I think it happens in CS GO because game graphics are at highest and PC isn't supposed to make more than 300 frames...

Besides Rust I play CS GO which isn't demanding so it runs at 200-300 FPS while GPU and CPU are working at around 50%.