We have developed just this[1] except using a MariaDB storage engine (MyTile) we've written. You can serverless run queries against TileDB arrays without spinning up a MariaDB instance. You can run any type of query MariaDB supports (joins, aggregates, CTE, etc). I've linked the basic documentation and an example notebook below[2]. You can run SQL queries from python/R or even JS or curl. We support a number of data return formats, i.e. arrow and JSON to facilitate use cases.
I'll also mention that we have a number of public example dataset[3] in TileDB cloud, such as the NYC taxi data used in this notebook[4], which you can explore!