Start up problems

Ok hoping someone might have some insight on my problem.

Recently built SFFPC and finally got the last piece (OS) and installed. The installation went perfectly, which made me nervous. My instincts told me a perfect install just ain't right. Installed all my programs, games, etc and mandatory W10 updates. Did my first restart and that's where everything went wrong.

Specs:

Gigabyte X570i Aorus Pro Wifi ITX / AMD Ryzen 5 3600 / 2x8 Corsair LPX RAM / Adata SX8200 M.2 SSD / Silverstone FX350G 350W PSU / MSI GTX 1660S ITX

Initially got stuck on 'preparing automatic repair' loop and couldn't suss what was causing it. Started by downloading latest BIOS update and installed from Q-flash. Went ok. Still no positive result. Then worked back from installed components and started by taking out secondary ssd storage drive (Samsung750 Evo 250GB). No change. Then removed slot B1 RAM stick and that changed everything. Allowed me to reach the troubleshooting section of windows but now each 'repair/redact' option comes up against another wall.

I'm at a loss as to why the RAM should cause problems when the board is designed to have two sticks. Fans are working fine and keeping things cool. BIOS shows everything doing what it should. However, even with the progress beyond the RAM I cannot get back into a full windows load.