Index maintenance on pg_catalog tables in AWS RDS

I have had some bad historical usage on my Aurora PostgreSQL instance. Namely, connections that create a lot of temporary objects and some very long running transactions (which limits autovacuum). Now I have some very, very bloat pg_catalog indices. For example: pg_attribute has only 34k records but *pg_attribute_relid_attnam_index and pg_attribute_relid_attnum_index are 630MB and 450MB!* In total I have gigabytes of (bloated) system indices on system tables. However, I cannot REINDEX or VACUUM FULL these tables due to permissions. Is this situation correctable in any way? Or is my RDS managed database permanently hosed and I need to migrate to a new one.