It depends on the displayport version. DP 1.2 only supports 4k. DP 1.4 supports more. So if it’s an older display that only supports DP 1.2, you have to use the two screens hack. I never tried that, though.
It depends on the displayport version. DP 1.2 only supports 4k. DP 1.4 supports more. So if it’s an older display that only supports DP 1.2, you have to use the two screens hack. I never tried that, though.
Not sure what these internal connections are, but Displayport is both a plug and a protocol. You can use the protocol over thunderbolt and maybe other connections as well.