And how are you supposed to verify that the right packages have been uploaded?
The easiest way to verify that is by using a reproducible automated pipeline, as that moves the problem to "were the packaging files tampered with".
How do you verify the packaging files? By making them auditable by putting them in a git repository, and for example having the packager sign each commit. If a suspicious commit slips in, it'll be immediately obvious to anyone looking at the logs.
The packages uploaded in Debian are what matters and they are versioned.