I'd say Microsoft already has this with Dataverse/Power platform? It runs on Azure SQL Server but it is not exposed directly nor uses SQL server's ACL. Instead,

I'd say Microsoft already has this with Dataverse/Power platform? It runs on Azure SQL Server but it is not exposed directly nor uses SQL server's ACL. Instead, the available access points -- mainly its web API -- honor the permission system configured on the platform, whether it's coming from apps themselves, custom JS code or reporting tools like PowerBI. Users are of course AD users. Model-driven apps on Dataverse are exactly how you'd imagine MS Access if rebuilt as a SaaS product, and they integrate with Office in various ways. One Azure tenant gets one Dataverse database-- it's certainly intended to host multiple apps sharing the database. Main problem is that building meaningful LOB applications on this type of low code platform is difficult. Works well for a toy project, or ends up being engineered solutions maintained by IT -- neither hitting the sweet spot mark. I guess general purpose low code is hard.