Described here https://blog-doe.pages.dev/p/my-front-end-state-management-a...
I've already made improvements to that approach. decoupling of backend and front end actually feels like you're reducing complexity.
Example is a bit bad, but roughly shows how we're using. I have built a custom sync API that accepts in the body a list of <object_id>:<short_hash> and returns a kind of json-list in a format
<id>:<hash>:<json_object>\n <id>:<hash>:<json_object>\n
API compares what client knows vs. current state and only returns the objects that were updated/created and separately objects that were removed. Not ideal for large collections (but then again why did I store 50mb of historical data on the client in the first place? :D)