DVI on Z390 m build?

Hi everyone!

Like many here, I'm running a gigabyte z390 mAtx build and am on a Radeon RX590 (seen by MacOS as a 580 but oh well)

Now, my old but gold 30" Cinema display has only a DVI port, and with a regular adapter to displayport or HDMI, I'm getting low resolution only, due to the single port nature of adapters.

Now my Z390 does have a DVI port on the mobo, I run my build stable with internal graphics on (I'm guessing for HW accel?) but my DVI is not picked up by MacOS at all. Do I have to install a kext to get this working? I usually just connect stuff to the GPU but this time it's different:D

Thanks!!