Having Multiple NVIDIA GPUs in one System

Hi there I am trying to switch to Linux. But since most Games I play have an Anti Cheat i want to use libvrt with GPU Passthrough since the Performance loss is pretty small and a Friend uses it without any Problem. But if i want to pass my main GPU (RTX 3060 TI) to the VM I need a second GPU for my Host and because i recently got a AMD Ryzen 7 5800x without an integrated GPU i cant use it for my Host. I had an old NVIDIA GT 710 lying around. So I installed it and my installation broke. Well it was technically still usable but only one Monitor was usable and I had to set the Screenresolution manually through the /etc/default/grub File and i could not install any Driver. So I reinstalled Zorin. Now I want to know what I should do to Prevent this from happening again.
I am Sorry for any Grammar or Spelling Mistakes I am not a native Speaker.
Thank You in advance.

Since they are both nvidia cards, did you enable sli mode (crossfire) in the nvidia console? Are both PCIe slots the same (both x16 slots)? Did you install the bridge for the cards?

In the nvidia console, it should see both cards and you should be able to configure each monitor for a specific card.
Do the cards support at least 2 heads?

Much of this can be answered by a quick check of your motherboard manual or the video card specs.