Just went into the relevant BIOS section and changed the option from Auto (which was resulting in 2133mhz) to 3600. I haven't really messed with DOCP yet but I could perhaps look into it when I have the time available.
Ryzen 9 3950x. Sorry, I should have included that with my original post. I'll definitely give that a shot. Thank you very much for the thorough answer!
Is the difference between 3600 and 3000 really negligable? I don't have much experience here, but I thought RAM speed made a big difference under Ryzen?