killing idle_connections

I have two DB's in prod 

- DB 1 has pg12 and pgbouncer for connection pooling

- DB 2 has pg10 and F5 for connection pooling

Both DB's have a max connection of 500.

During pick hours i always run out of connections, even though i have 3 superuser reserved, my connections still go beyond 500.

So when I try to check active, idle and idle_in_transaction, this is what I get.

   5              

  24             active

  4               idle in transaction

  414           idle

most of the time idle  connection is at 400 plus or above 350.

So i created a script to kill connections that have been idle for 20 secs and the cron run every 1 minute. After a while, i started getting this error from developer "57P01: terminating connection due to administrator command".

I understand that connection pooling is designed to reuse idle connections and if you kill them, you are actually or probably killing a connection.

Or maybe the time i set for the script to run is too aggressive?

Or should I not run the script in the first place since connection pooling handles idle connections?

Does anyone have any suggestions to overcome my connection problems?

I have also done OS tuning and I am convinced they are okay.

Any ideas🙏

Many Thanks

Ndoh