This seems like the type of thing that a sophisticated query planner in 2024 would be able to figure out on its own? Maybe as a non database expert I'm expecting too much?
There were attempts to do this automatically ~7 years ago (https://www.postgresql.org/message-id/flat/7f70bd5a-5d16-e05...). It didn't actually make it in due to worries about the approach and properly de-duplicating the final resultset, as well as that approach to the optimization not playing well with duplicate inner-join removal optimizations (which were also being discussed at the time).
