GPU passthrough is not easy, thankfully there are guides online, but I did have to do a bit more digging after an issue I had.
You do need 2 GPUs, on a laptop it’s not an issue as most of them use an intel or amd gpu to render the desktop and only use dedicated graphics for intensive tasks, but on a desktops, you don’t have that option and you’ll need to turn off the graphical portion of linux, making it accessible only through something like ssh