Just a few days ago heard about Mangohud, a Msi Afterburner/RivaTuner "clone" for Linux and it does the job perfectly.

It's a tool I've been searching for quite a while and to my knowledge there's nothing alike on Linux. I've used some tools like Conky previously but never managed to make it work as good as Rivatuner.
It has a nice configuration tool as well, including a setup to cap FPS or unlock it, couple of screenshots below.
IF it gets your interest, the link to the Git page is here

So that is what it is called. I have seen others use it. Installing right now.

Neat. Snagged it off my local package manager, will poke things with it.

Yeah it's awesome, frame timings and everything.

There's a bunch of benchmarks on youtube by FlightlessMango, that uses this HUD to compare Vulkan/DX11/Wine+DX11 between Linux and Windows.

Made some headlines with RDR2 and Doom Eternal getting (slightly) better performance on Linux.

In the OP screenshots it doesn't show GPU statistics because was using Intel integrated graphics, it work flawlessly with the AMD card. Will check it, out of curiosity