...again.
I had this happen a few months ago and the solution was to update my bios. Now suddenly, smart access memory decided to be unavailable once again. If I have to risk my PC by updating my bios every few months (small risk but still) for this feature to work, I might as well consider it non existent. And yes, above 4g decoding is enabled in my bios.
5800X, 6800XT, driver version 24.6.1