Recently installed Leap 42.3/new to linux in general. Specs: AMD 1800X, GA-AX370-GK7 from Gigabyte, 2x8GB DDR4 3200MHz RAM, Samsung 950 Pro 256GB M.2, Nvidia GTX1080.
Upon installing XEN and rebooting -> selecting OpenSUSE w/ XEN -> starts loading, but rather than going to a GUI it goes straight to terminal. I would normally be able to fix this by installing the necessary updates, however my screen keeps flashing. i.e I can see the terminal login screen, but then it will flash and get stuck on a blank screen with a “_” in the upper right corner of the screen for a few seconds and it wont let me properly type in my username/password. Anytime I do and hit enter it says wrong credentials. Not sure if this is kernel/software related. I do know for a fact it’s not my HDMI cable, GPU, or monitor.
You’re most likely the only guy in the universe to use Xen and 1080 
That being said, you could try booting with nomodeset as a grub parameter; when presented with the bootloader, press e to edit parameters. Scroll down to the line where it says linux and the xen -kernel, add nomodeset at the end and press CTRL+X or F10 to boot with this parameter.
I need some sort of virtualization for a few VMs, one for work and one for gaming (the games that don’t run native under Linux, might try out Wine or waylend, or whatever it’s called) and others as needed.
EDIT:
When I add that in to the XEN boot option, it got even worse. To were it switched between the things it showed during boot and the login terminal prompt at the end every second.
Will try uninstalling XEN and try a reinstall.
I’m not sure why you opted to use XEN when KVM does everything it does and doesn’t require a separate kernel.
I didn’t know that, I’ll try KVM then.
You can install KVM and related tools (and setup the necessary networking bridge) from YAST / Virtualization / Install Hypervisor and Tools.