Just going to state first I am using Process Lasso Pro.
For me every time I start 7 days with EAC on its getting only assigned to my efficiency cores which are garbage at running anything other than background tasks.
I have a Intel i9 12900ks 16 core, RTX 4090, so ideally id prefer to have the game restricted to just the performance cores as those run at 5.6ghz, or if thats not possible then have the game run on all cores. I've noticed this especially makes a difference when running the game at 4k with highest graphics settings, running on efficiency cores vs performance cores means the difference of about 30 fps.
I found that if I made an affinity rule for 7DaysToDie_EAC.exe for cores 0-15 (my performance cores) with a delay of 0 I was able to have 7DaysToDie_EAC.exe and 7DaysToDie.exe would inherit that affinity (although I also had a rule for it but it was never applied)