Try the Heimdall Proxy. It has shown to improve Odoo scale up to 20x without code changes. The problem with most proxy and load balancing solutions in the market is that Odoo queries are in transactions and strong consistency is required. This eliminates all known solutions to split queries in the market, except for Heimdall Data.

The Heimdall Proxy is the only solution for Odoo that can 1) Query cache and 2) Split read/writes transactions with ACID compliance. Check out: https:/www.heimdalldata.com/odoo