DBD suddenly runs terrible with my new PC

I just built this pc like 2 weeks ago. I really only play DBD and like 4 games. All installed on an external HDD.
When I first installed it, I could run it smoothly at 60 fps medium graphics, 100% resolution scale. I thought it was a little blurry so I turned AntiAliasing off with the Engine.ini file. The game and the gpu temperature was way better. However, I didn't use my computer for a few days (nobody used it in my absence), so when I came back the game suddenly drops to 35 fps in the lobby and I can barely max 50 fps. I already deleted the lines for antialias and it didn't got any better. Task manager also doesn't show any other program using gpu.
Why is that? Did I do something? Can I change something to help it?
My specs:
Ryzen 5 3500X
RX 470
16GB Ram 3200 mhz
SSD 480 GB
HDD for games 1TB 7200 rpm (DBD installed here)
Motherboard MSI B450 Pro M2 MAX
Comments
I'd highly suggest moving to an SSD,but also 5.5.2 has been notoriously bad on the performance.