Fortunately, AMD seems willing to enable bifurcation on all their desktop platforms instead of using Intel's strategy of treating it as a product segmentation thing. Quad M.2 risers work in both my B550 and X570 system.
*: I know there are other reasons for non-K processors (binning might actually mean your non-K CPU can't overclock), but it's largely just a way to move more product and sell at a lower price point to those who can't afford unlocked or otherwise wouldn't have overclocked.
(Binning because of imperfect production yields is different though and I don't have a problem with that. It's hard to tell how much of the K/non-K split is legitimate binning, and how much is just a bool in the microcode).
https://www.amd.com/en/technologies/smart-access-memory
Or that time x470 was going to support PCIE 4, but then it was made x570 exclusive