Can't get past login screen after installing a new GPU

Hello everyone,

I have been running a Dell Optiplex 9020 (i5-4570,16GB,500gb Sata SSD, using iMac20,1 SMBIOS) with the iGPU for the last few months and it's been great. However, I recently replaced a GPU so I have a Red Dragon RX580 on hand that I wanted to install in the tower (replaced the PSU a while back so it has the right PCI power connections). I am able to boot in safe mode with no graphics acceleration and it picks up the card with 8gb VRAM. However, when I boot normally it won't let me get past the login screen, instead going black after I enter the password and returning to the login screen. I'm guessing something is crashing during the login procedure, but can't tell what.

I have tried iMac Pro 1,1 SMBIOS, but the results are the same. I also removed the boot-args "keepsyms=1 debug=0x100", as I originally booted to a black screen and this fixed it, but now i'm stuck not being able to log in. I also used it in an eGPU enclosure for a previous hack (NUC macmini) and it worked fine there, so I believe it is a compatible model. I also made sure LILU and WhateverGreen are up to date as well.

I feel like this is going to be something simple, but i've been beating my head against the issue for a couple of hours and thought I would ask the experts to see if they had any thoughts.