It's very similar to what Meteor project (the most popular Full-Stack framework sometime in the past) tried to do:

In its beginning, the query language of the project was Mongo and not SQL, but this was almost the only difference between Meteor and your post.

In order to enable all the goodies that you detailed in your post, they developed a browser-side Mongo ("MiniMongo"), in addition to the real MongoDB running on the server-side.

One of the reasons for preferring Mongo over SQL, was the belief that such a challenging idea will not work with a complex query standard like SQL, but Mongo is simple enough for this purpose.

Then everybody wanted SQL in Meteor.

In a survey of Meteor, this request achieved more than 1000 results, while features like connection to Angular achieved 40 results and less, but were developed, and the company behind Meteor hadn't done anything regarding the real request, SQL support.

So there were some independent projects of Meteor developers (I remember one of somebody whose name was Ben Green, IIRC), that used browser side SQL libraries (like knex.js), and succeeded to repeat the 2-level DB, but this time not with MiniMongo and MongoDB, but with browser-side SQL and server-side PostgreSQL.

It was very promising, but then the company which owned Meteor decided to replace most of its parts by parts from Facebook, and to rename it "Apollo". For example, the super-easy view framework, Blaze, was replaced by the monstrous ReactJS.

The browser side SQL became unnecessary because the whole data model was replaced by GraphQL.

I've claimed through the whole process, that it was a big mistake, and that the original Meteor was a so genius framework that should not be rewritten from scratch with different components.

Instead, they had to leave it as is, improve the performance, and move to SQL, as the independent implementations succeeded to prove that it was possible.

I didn't learn each source code line of that implementations, but I think that they used some of the ideas that you write about them here.