I'm running a few desktop web browser/printing kiosks with Ubuntu 20.04 for our warehouse on Raspberry Pi4s, which is arm64/AArch64, so a deb built for this platform would be very useful. I don't know what your build platform is, but it should be possible to setup build environments with docker/qemu or other virtual machine systems.
Kernel "uname -a": Linux localhost 5.8.0-1016-raspi #19-Ubuntu SMP PREEMPT Tue Feb 9 20:12:43 UTC 2021 aarch64 aarch64 aarch64 GNU/Linux
I commented on this other feature request as well asking for the same thing.
Customer support service by UserEcho