So it looks like you have python39-pulp-deb version 2.20.2-1, which is the version with the fix for the orphans cleanup, and it looks like the migration (number 0020) from that version is applied.
My one other idea what might be causing this is a client bindings incompatibility. Katello 4.8 currently has access to rubygem-pulp_deb_client-2.20.1-1.el8.noarch.rpm, the rubygem-pulp_deb_client-2.20.2-1.el8.noarch.rpm client is in the pipeline for Katello 4.8, but has not been added to the repo yet. However, you can get it from the nightly Katello repo. So try downloading the following onto your Katello host:
http://yum.theforeman.org/katello/nightly/katello/el8/x86_64/rubygem-pulp_deb_client-2.20.2-1.el8.noarch.rpm
Then just install it with dnf installl ./rubygem-pulp_deb_client-2.20.2-1.el8.noarch.rpm, then restart everything with foreman-maintain service restart and see if that fixes your issues. If that solves the problem, I will need to ping the Katello team to put a rush on adding the newer client version.