Refresh materialized view on Postgresql 11 on RDS

We are currently on Postgres 11.13 on AWS RDS. I am trying to create a materialized view that takes about 6-7 minutes to run. What is the best way to keep this MV mostly up to date? I was thinking of pg_cron but I believe that is only available on PG 12.5+. A trigger on the underlying tables could be an option, but these tables either do not get updated at all, or underlying tables have many many inserts that occur in a short period of time. I don't want to trigger excessive refreshes. Any suggestions for this scenario?