(macOS HS) can't get past login screen (throws me back to the login prompt)

I was on Mojave with my GTX 780, but upgraded to a GTX 1080 so I had to downgrade my mackintosh because of Nvidia drivers

now that the install is working and it's actually running, I can't get past the login screen (I have auto login enabled and yet I still need to put in my password)

whenever I try to login, it tries to load the desktop and then throws me back to the login screen where I can type in my password

in safe mode it lets me login, but that's obviously no solution

my setup : Xeon x5650@4GHz, 16GB 2005MHz RAM, Asus P6x58D-E, GTX1080 (main 1440p 144hz G-Sync monitor) and GT 710 (secondary 1080p monitor), High Sierra is on a 120GB Toshiba A100 SSD

would love a fix to this, thank you and Merry Christmas