TLJH on M1 Mac (Arm) Docker: installer is x86-specific

I attempted to follow directions for installing TLJH in a Docker container on my M1 powerbook (ARM architecture). fails because contains a URL that is specific to x86 architecture. Is it possible for the installer to be architecture-agnostic? If not, documentation should be updated — requirement is is not just Ubuntu linux, but rather Ubuntu linux on x86 specifically (so users of ARM machines need to either run Docker in an emulation mode or find another machine to install on).

There was some work on getting TLJH running on an RPi which should also work for M1?

It seems that the PR that arose from the discussion is still unaccepted: