preempt=full nohz_full=all ("realtime" kernel features) have never made a difference for me on Fedora 43/44. That said, I haven't experimented with modified kernels -- there might be value here. Let us know what happens if you try these. I also plan to try the BORE scheduler at some point.
I've also tried setting SCHED_RR and SCHED_FIFO on host VMware processes (eg vmx-vcpu, main-svga, main-mks, etc) to no avail. In a heavily-loaded system with processes fighting for a CPU timeslice I reckon they could be helpful. But in my case they did little or nothing. Same goes for renice and setting process priority level.
init_on_alloc=0 init_on_free=0are security-related and deal with ensuring memory pages are zeroed-out before+after use. Some feel this is belt-and-suspenders overkill and are fine with disabling. For most workloads it seems to make no difference but there's a handful of corner cases (OpenZFS is one) where they definitely move the needle. I've benchmarked this setting on the host but never in a guest. Older nVidia GPU drivers would malfunction with this -- I believe it was fixed ~6mos. ago.
mitigations=off is a blanket disable for a heap of processor mitigations including Spectre, Meltdown, RetBleed, L1TF, and many others. It matters less with newer CPUs but even with my AMD Zen 4 I can show significant benefit given the right workload. For me it's more effective as a host setting. Useful but smaller benefit in a guest. You'll have to make the call on security vs. performance here.