Old tech and hard to find info, but there were two different graphics (core/generation ?) cards Oland and Cape Verde.
I believe the Cape Verde options did not support dual graphics mode. I do recall it being mentioned about some Sapphire models on some old tech spec sites.
Ryzen 5 5600x, B550 aorus pro ac, Hyper 212 black, 2 x 16gb F4-3600c16dgtzn kit, NM790 2TB, Nitro+RX6900XT, RM850, Win.10 Pro., LC27G55T..