sjameson

Just for anyone else who finds this thread down the line:
 
SeaBIOS will not work with my setup due to the GPU requiring UEFI for passthrough. I was able to restore to a previous backup with the following steps (the custom XML VM provided above did not work as it wouldn't boot with my GPU due to the BIOS being changed to SeaBIOS):
 
Created new nvram folder in etc/libvirt/qemu for my OVMF VARS files
Copied backup .fd into the newly created nvram folder (make sure to remove the timestamp from the beginning of any backup files)
Copied backup vdisk1 into my domains folder associated with this VM
Copied old backup libvirt.img (xml and vdisk 1 were from late July, and the libvirt image was from back in January) and replaced the current libvirt image in /mnt/user/system/libvirt/libvirt.img
 
Used the xml to create new windows 11 VM via xml mode
 
Everything booted up at that point and I only lost a month's worth of software that I had setup (no important documents, just the software packages themselves). 
 
Probably going to rethink my backup strategy for VM's now and make things more automatic. I stopped doing automatic backups because I had to shut down the VM in order to do so. Not sure if I want to redo everything and try to start using snapshots instead, but I'm not sure how straightforward that conversion would be. Likely going to just do more frequent manual backups after major changes to software/settings that I want to persist.
 
@bmartino1 I appreciate the help! Your solution will likely help a lot of other people, but didn't quite help me due to requiring UEFI boot for my GPU passthrough.
 
Long story short: if you have a .fd VARS file for a backup restore, but your nvram folder is gone, just create a new nvram folder where it should go (/etc/libvirt/qemu/nvram/) and copy your .fd file in there and start up that VM!