I have built one PC already paired with 5500, BIOS already updated for it. PCIe Gen3 NVMe and 3200mHz RAM all worked for me. The expension slots can fit a 2-slot graphic card and a PCIe Wifi card.
Maxsun is also used heavily by Techfast in their prebuilds.
3+2 phase with descrete MOSFET, no issue to handle PBO at 75W PPT with 200mHz overclock, I would recommend a downdraft CPU cooler though.
It is smaller than mATX, and fits in Cooler Master NR200 ITX case.
There's also some recent discount codes posted for aliexpress if anyone's buying.