How can I find what's eating so much space in Postgres in AWS RDS Aurora?

Question

Essentially when I run

SELECT
   pg_size_pretty(SUM(pg_total_relation_size(relid))) as total_size,
   pg_size_pretty(SUM(pg_indexes_size(relid))) as index_size,
   pg_size_pretty(SUM(pg_relation_size(relid))) as actual_size
FROM pg_catalog.pg_statio_user_tables;

I get

And when I run

SELECT pg_size_pretty(pg_database_size(<MY_DB_NAME>));

I get

Because of this, our storage bill in RDS is massive, and I don't know what else to search for. Unfortunately, I don't have access to AWS Technical Support