Afternoon,
I figured out how to at the very least be able to convert the ARM64 iso's
to isohybrid on the same system they're built on. It involves some simple
wizardry on the host system, installing qemu-user-static and installing
syslinux-utils from the amd64 repository. Sadly that means I have to run
the command manually, but, at least we have some sort of solution.

If anyone wants to have their hands on the Netinstall or Desktop ISO I have
built for ARM64 for their own independent testing, please contact me and
tell me how you would like to have it transmitted to you

-John