It can be done manually:

https://dba.stackexchange.com/questions/306661/how-to-instal...

Assuming if it's for a support team or internal users with a lower SLA, I wonder if it's possible to have a small self-hosted PostgreSQL server that basically acts as a shim by holding a foreign-data wrapper connection to the actual RDS instance

In RDS, if you cannot use this, you can create masked view and use query rewrite to make it work.

In my experience PG anonymizer has performance issues when it comes to large queries.

+1 for RDS support. I have wanted to use this for a while in our production systems. reply

Same. Lack of RDS support is the only reason we aren’t using this.