The key will be UN membership, which they may be able to get.
UN membership is not absolutely essential. If the ITU assigns Catalonia prefix (as in the case of Palestine), then it shall count as a new entity for DXCC.
And since the ITU is an arm of the UN, the UN at least recognizing the state is essential.
So my point stands. (and this is why Kosova isn't yet a DXCC entity)