If pulpcore 3.39 did fix this issue, then that would be a “happy accident”. AFAIK the Pulp team is not currently aware of any performance regressions in the versions that ship with Katello 4.10 (other than having been told about the existence of this thread).
The last big performance issue from the other thread should be fixed in the Pulp versions that ship with Katello 4.10. As we learned from that issue, performance issues are sometimes dependent on the postgresql version used, and the Pulp team generally tests with a newer postgresql version than the one shipped on El8 (and by extension what is used by Foreman/Katello). As a result it is entirely possible that you have hit a performance issue that the Pulp team is not aware of from their own testing.
If you did want to dig through the Pulp release notes, see: Changelog — Pulp Project 3.44.0.dev documentation
Note that “Resolved a sync-time performance regression. #4591” is the fix that is already included with Katello 4.10.