If you want to speed up the getters (without support for nested queries), as an experiment, why not try replacing each getter on Container with two calls to queries, the first to get the bucket from the container, and the second query the bucket itself. I expect two queries will still be much faster than one nested update call.
This won’t lead to any improvement for canisters getting data, but should speed up any frontend getting data.
Curious to see what the performance results are, or any reason this should not work.
Even better would be if the queries were certified, but that’s a lot more challenging…