I see that this is very feature limited. As other threads have noted the more recent video cards (at least nvidia) also support hevc/265 and AV1 with HDR which are superior to avc/264 in almost every way. Also audio in opus is preferred.

When I screen record stuff on linux I use this https://git.dec05eba.com/gpu-screen-recorder . It has a very small cpu hit when using and it works great, even with AV1/full screen/143fps. This might be of interest to check out how he accomplished it. I wrote a quick bash script to mimic the functionality of using nvidia on windows and it works great.