None of the consumer Navi 2x cards are 'officially' supported. Nevertheless, you can use the ROCm libraries anyway by setting:
export HSA_OVERRIDE_GFX_VERSION=10.3.0
That will make your gfx1031 card pretend to be gfx1030, which is a supported architecture. Those processors were given different numbers in case an incompatibility was found, but I haven't heard of any thus far.
Obviously, that's not as good as official support, but I hope it helps.
They're not 'officially' supported like you say, but Navi21 cards (6800-6950xt) have undergone the same QA validation as the officially supported pro cards.
Obviously, that's not as good as official support, but I hope it helps.