Does this blacklist some regions of my RAM? Maybe we need to blacklist more?
Yes, there is a firmware bug on 64GB devices causing those blue screens and removing the upper 32GB of RAM is the only known working fix of at this point. Maybe I got the mask wrong, try adding cutmem 0x8800000000 0x8fffffffff at the start of your /boot/grub/grub.cfg manually, that is what we do in our installer to make things work.