On MacOS the Radeon Pro 580X can use two Apple XDR (HDR) 6K displays 6016x3384 at 60Hz or two 5K displays 5120x2880 at 60Hz.
I bought one 21:9 5K display 34WK95U from LG 5120x2160. It' a certified hdr monitor with thunderbolt 3 port.
Well, the HDR mode is not available on MacOS and partially...