Nothing unusual in xorg.conf but as soon as ForceCompositionpipeline gets enabled, Xorg log reports slowdowns, also dmesg reports it. No excessive irqs, though.
You have nvidia-drm.modeset=1 enabled on kernel command-line, shouldn’t make a difference but please check if anything changes when you disable it.
Also check for module options files:
https://forums.developer.nvidia.com/t/ubuntu-18-04-3-blank-screen-at-startup-with-430-drivers-and-gtx-960/107501/2?u=generix