Postgres Vaccuming

Hi Team

We are facing some performance issue with in-house infrastructure because of the size of postgres dbs. I am creating a vaccuming automation for the postgres and wanted some help/opinions from the community.There are 4 dbs in the of postgres( apigee, posgtres, template0 and template1) The first db apigee is the heaviest out of the all and definitely has transaction data in it.

Does any one know if there is any transaction related data in postgres, template0 and template1. I think template0 and template1 should be system tables.

What we want to achieve is to :

backup the data

vaccum the data and retain data only for a few months

Recover the data in case of any issue

For point 1 i need to know which all tables should i backup.

Thanks for you time

Regards

Sumeet Chawla