Hi, i wanted to mention this here, as even though i don't use Unraid, this thread is one of the biggest resources about C-state issues and powertop.
I recently built a homelab server with a B760M DS3H DDR4 mobo, and was unable to reach package C-states higher than pc3.
The solution turned out switching M.2 slots to the non-CPU one.
Note: This MOBO also has the problematic Realtek 2.5 Gb port, for which i switched to the r8125 driver, and i haven't tried switching back to the default (in-kernel) r8169 driver.
I hope this can help someone else avoid some headaches.