What... are you doing in the background? I've got a 3070 and 4k monitor, and I get between 50 and 60 FPS with all the settings I can fiddle with disabled enabled. I use RivaTuner to pipe statistics to a little application that drives my Logitech G19 with a real-time frame graph, CPU usage, memory load and GPU load and it uses multi cores pretty well, and generally makes use of the hardware.

-- edit -- Thanks for pointing out I made totally the wrong comment above, changing the meaning of my comment 180°...