So I did reinstall it and it did work. I’m a bit confused because I used the same ISO file, same USB, same computer, etc, and there was zero differences from what I can see from my third attempt reinstalling it. I guess I shouldn’t question it; it seems to be working currently.
It was after installing and booting up the system, I kept getting an error about a PCI device. I fixed it by using this here, but after fixing that issue I then got the Libxenlight error.
So it was immediately after installation, I hadn’t actually used Qubes OS yet in this stage, but it wasn’t the first error I got after boot up, if that makes sense.
Thank you @oxygenlast & @apparatus for suggesting I reinstall it, it seems to of fixed it (at least for now).