I have a very strange bug where I boot qubes, get to the decrypt disk screen but it is completely blank. I type my password and then the loading bar and screen appears, and Qubes seems to work perfectly.
Is there a GRUB command I can add or something to make it text only, hopefully that will enable to at least see the amount of characters typed - I literally just have to type to a black screen and hope I entered it correctly!
Try pressing e in the Grub menu screen, remove the string rhgb (Red Hat graphical boot) and maybe also quiet after it from one the lines, and press Ctrl-x (IIRC) to boot.
If that actually helped, you can make text mode boot permanent by removing the same string(s) from GRUB_CMDLINE_LINUX in /etc/default/grub and running sudo grub2-mkconfig -o /boot/grub2/grub.cfg.