Detailed action plan to reduce postgresql AWS RDS size

Our RDS is getting bigger which need to reduce the size. Our PostgreSQL DB schema is complicated with 100 tables and a lot of dependencies (foreign keys) The project is about backup old data, remove the data, then migrate to a new RDS instance but use the existing endpoint naming so the application can still. Before I give you the PostgreSQL DB and show our environment to you. Please tell me about what your success experience of managing postgresql DB and AWS RDS, as well as general idea about your solution. (no detailed information required) The project steps: 1. I will investigate your general ideas and assign the task to most suitable bidder 2. I will show you our real environment. 3. Send me your detailed action plan to achieve the goal. Please note that the plan will be revised according to my understanding. 4. Fix any concern I raised 5. I will act according to your action plan. 6. If all success. I will release the fund to you. Please note this project may back and forth many times. Please only bid if you are willing to revise your action plan based on my questions.