To be able to use arm hardware, we need to refactor build script.
You don’t need aptly for basic compilation, but when build packages in chroot (extras-buildpkgs) and for providing .deb repository. I noticed there are only x86 packages so we would need to build it for arm64. And another problem is that project is not getting sufficient maintenance love. Mainly trouble for CI usage on arm64.
Excuse my stupidity, but what is the essence of the question ?
Another issue. Our build system uses aptly for backend and advanced building. Which was never build for arm64 yet and its they are looking for new maintainers for some time …