postgres database with multiple database object owners and pg_dump with a postgres 11.2 database with multiple database object owners and trying to use the following command as the database owner (not the postgres superuser):

pg_dump  -h hostname -p 5432 -U dbownername dbname --file= dbname_20200406.pg_dump --no-owner --no-privileges --format=p


it fails due to object ownership not being all the same. (I have tested that this is the case by changing all ownership to dbownername and at that point pg_dump succeeds)

is the only way to get this to work is to run it as the postgres superuser?  or are there postgres roles that I can give dbownername to allow them to back up... with out in effect making them another postgres superuser?
If you grant SELECT privileges to all tables to the database owner you should be able to export at least the tables. If not, please give full error message(s).