Can you explain what all would be needed to make a similar setup? I see the dongles for ~30 but does it need to be in a location with another piece of hardware or what?
Correct, the dongles connect via ethernet cables (not ip protocol) to the raritan unit. Then you access the raritan via IP to access the dongle outputs.
There is a great video from Level 1 Techs where he explains why he started making KVMs and why it is an extremely hard problem. (Edit: I can't seem to find the video now, it might have been on another channel, but I'll keep looking)
The TLDR is that manufactures don't follow specs as closely as you'd think, and as a KVM you have to handle the bugs of thousands of different manufactures for both upstream and downstream devices.
For each connected device you need a dongle, which is what will plug into the display and usb ports of the server.