SOGS compression keeps coming up here as a go-to method for reducing Gaussian Splatting model sizes. I put together a deep dive into how SOGS actually works under the hood, with some practical insights on how it can be used in production.
The article stays fairly high-level, but I'm happy to dive into specifics in the comments. I learned quite a bit from implementing my own version of SOGS compression.
I'm not convinced that there is one generalised solution to sync engines. To make them truly performant at large scale, engineers need to have deep understanding of the underlying technology, their query performance, database, networking, and build a custom sync engine around their product and their data.
Abstracting all of this complexity away in one general tool/library and pretending that it will always work is snake oil. There are no shortcuts to building truly high quality product at a large scale.