I'm having an issue with Rancher Desktop on an M1 Mac where no matter what I set the memory allocation to in the VM, the node only reports that is has 2948.3Mi of memory.

You are probably on an old version of Monterey. There is a bug that has been fixed in macOS 12.4 and later that would allow you to allocate more memory to the VM.

I will update and report back, thanks!