Sorry I am a moron... I switched the board to a
ASUS TUF GAMING X570-PLUS
On suggestion in this thread.
Experience next-level gaming with TUF GAMING X570-PLUS (WI-FI): AMD Ryzen ready, enhanced cooling, superior connectivity & game-changing durability.
www.asus.com
It lists 2607 for 5900 and 5950 ... but doesnt actually list 5800 .. I just figured + stuff I gathered for a variety of reddit posts that the 2607 should do it.
To answer your other Q's. No. Nothing spins up. Its not the case connectors, I am using a good old trusted screw driver to short the pins...
But as I said, there is those pesky led's on the backside of the board doing a dance (only when 24 pin atx connected).
Its all going out on a cardbox board today or tomorrow for minute inspection.