AMD has their own kind of management system available on some machines (DASH, using "smart" NICs like Broadcom), but the PSP isn't even involved when DASH is available and in use, as far as I know.
However, on my Intel machine with AMT, there's a network port opened by the ME itself (TCP/16992). It can use the same IP as the main OS, or a different IP entirely if desired. It uses the same ethernet port as the main OS though, splitting the packets that are directed to one of the ME ports and selectively allowing the rest to continue to the main OS (there's a low-level ME firewall[1]).
On that port, there is a full remote desktop with mouse and keyboard, the ability to remotely connect small drives and/or ISO files, a remote serial console, a low level firewall configuration utility, and power/reboot controls. Even on machines where AMT is not even supposed to be available, there have been PoC demonstrated using one of the ME flaws to turn it back on[2].
[1] https://i.imgur.com/Wphopk1.jpg
(slide 68) [2] https://www.blackhat.com/docs/eu-17/materials/eu-17-Goryachy...