+1 to Hugo's point: We used 'fpm' for building our
internally-distributed .deb files; then we used apt-s3 (or whatever
it's called) to, well, pull the .deb files from an S3 bucket. Prior to
that, we used the full debbuild toolchain, but it was overkill for
internal releases. For simpler .deb files, we just built them with a
shell script and 'ar', etc.
otoh, if I were to do it again, I'd go all-in on containers.