Freeze on welcome screen after AMD driver update

About 3 months ago I updated AMD drivers for my R9 290. Immediately after I started having problems booting Windows 10. Right after post and before windows loading screen appears, a never-before-noticed black screen would flash on/off with a white underscore cursor in topleft, then again with cursor lower, then again with cursor to the right. This would happen over 1-2 seconds, then repeat 2-3 more times before Windows loading screen appeared. About 80-90% of the time after loading screen finished, Windows 10 would not let me in.

Path 1: screen would go black, showing normal mouse cursor and nothing else. No way to do a "blind" login as others have discussed online, only option to restart and hope for best.
Path 2: same as option 1 but with light gray screen.
Path 3: the beautiful welcome photo would show, but wifi in lower right would never connect, and screen would not respond (normally it shoots upward revealing login screen). So again, no options but hard reset and hope for best.

It would take upwards of a dozen tries to successfully log in. Once logged in, behavior was totally normal. I tried reinstalling latest and 2 older versions of AMD GPU drivers, always using their "cleaner" app that removes all AMD related files. Nothing changed. I switched to a NVIDIA GPU (Strix GTX 1080) and installed their display driver, same problem returned.

Important note: Of the many solutions suggested for these problems online, the only one that worked -> 100% SUCCESS when removing all GPU display driver files and/or booting with special option 3 (low-res boot mode). This told me drivers were definitely the issue (whether directly or indirectly somehow...).

I reset all defaults on my BIOS. The weird flashing black screen with underscore cursor went away, and login success went up a bit, but still 30-40% of the time it would freeze in the exact same ways as before.

I reset Windows 10, removing all files/apps + clean drive option. Windows 10 installed display driver for my GPU on its own. Again, login success went up, but still 10% of the time login screen freezes, now only Path 3 as described above. I've restarted 30 or so times and 3 times it froze. EDIT: Just got one black screen 4-5 frozen login screens in 50 or so restarts...

I "refreshed" windows 10, thinking this would clean out old files that may have survived the reset. Still exact same problem as before, 10% freeze rate on login screen. I'm out of ideas of what to do, could this be a bios compatibility or dying mobo issue? My original build is about 28 months old. New GPU purchased a few days ago.

I did a disc Cleanup run, including system files to get rid of Windows.old. Problem persists. I'm relatively happy with 90% login success rate, but I can't help but worry the problem will someday bite me again and I'll go through this nightmare all over again...

OS is on a 512GB Samsung 840 Pro SSD

I have two other HDDs, one Backup drive with EaseUS backups, Steam games, and some random ETLLogs folder under "Diagnosis" that I don't know the origin of. Another drive with a bunch of instrument sample packs for music production software. Could there be a corrupted file in one of those drives contributing to my problem?