Boot issues - make no sense

[decto]

I'll try to keep this short.

Mortar B550
3700X
4 x 8GB 3200 CL14 8pack
RTX3070
1TB NVME

Working fine > 20 months until a windows update last night.
After the update, blue screen with 0x000000021A
It was late so turned it off.

Troubleshooting, won't boot into windows, error Ox00021A then recovery
Won't accept password for recovery mode. Keyboard entry correct (view plaintext)
Password is fine online or in my laptop on the same account. Changed password online, no difference.

Figured this has 2.5GB lan so perhaps driver issue for password in recovery not allowing sync with the MS server.
Added an old quad Intel NIC to the PCIE x4

Immediately boots to PIN screen, input pin and login to full desktop... super.
Remove card - same issue, no boot, password not accepted.
Add Quad NIC back in - boots perfectly - repeatable. doesn't matter if the lan is connected to the Quad NIC or the onboard.

I think the PCIE x4 shares lanes with the NVME

Going to do some install cleanup now while it's booted, but so far the strangist issues I've had in a while.

 

[decto]

Somehow posted in the wrong thread, could have sworn I was in GH.

Anyhow, looks like it will be a reinstall, if I uninstall the recent updates, windows reboots and immediately reinstalls them before I get to the login screen.
The issue is really odd though, PCIE x4 is shared with M2_2 which is not used so should be no reason an additional card lets it boot.