I tried these recommendations to both multiboot and multiboot2 command lines. Also, with module and module2 command lines. No new errors displayed.
Above mentioned behavior is still the outcome(also pasted below for easy finding)
If command contain multiboot I am getting
no multiboot header found
If command contain multiboot2 PC gives a blank screen and reboots after printing
Loading initial ramdisk ...
I also tried adding rd.qubes.hide_all_usb as mentioned here: https://forum.qubes-os.org/t/black-screen-before-luks-encryption-password-boot-prompt-after-failed-dom0-upgrade/17521/4
My next plan is to try, let me know if I am in the wrong path: UEFI troubleshooting