I agree with @few. There already exists a WiringNP, which is WiringPi for Nano PI from friedlyelec.
It shouldn’t be a big problem to fork the repo and include also RockPi 4.
The board is detected using CPU information in boardtype_friendlyelec.c. I don’t have any of the boards yet, but I do think that if you compile the repo the board will be detected as Nano Pi M4, which uses RK3399. In the wiringPi.c there are various schemas related to detected board. You should patch the GPIO schema of NanoPi M4 according to RockPi 4. An experienced programmer would need some hour to fork, patch and make the WiringPI for RockPi.
I do agree, that Radxa team should spend this hour of labour work to clone almost done work.
However, not all apps would work, even if you would have WiringPi implemented. Only the apps, referencing with header pin number shall work. For others you would still need to change the GPIO numbers in source.