So I actually did get around to solving this in the end and even though it took me a while to get to do it, I thought I’d update this thread for anyone possibly coming across the same issue in the future.
In my case, it must have been support for AMD’s SME (Secure Memory Encryption) being enabled in the kernel config.
I’m not 100% certain whether it was SME as I also disabled Virtualization support (in the kernel) entirely in the process, even though it was already disabled in UEFI, just in case the drivers detected that and raised a red flag.
I know Nvdia certainly doesn’t like it when users try to use their consumer-tier gtx cards for virtualization, so I figured I might as well disable it in the config as I don’t intend to configure any such setup for the moment.