@Silverman,
As long as you get a card that follows the AMD reference design then you should be ok, the RX 5XX series reference design has four output ports (1 x HDMI + 3 x DP) and has no DVI port. Some OEM ship their cards with different port configurations and some also have an additional 5th port (sometimes a DVI) ... these non reference designs can cause problems in MacOS as the different/extra ports are not included in the default AMD framebuffer's, in most cases you can patch the framebuffer (see the guide in Post #1).
You can use a DP to HDMI adapter if you need an additional HDMI port, as DP is fully backwards compatible with HDMI.
Cheers
Jay