It’s really best to design everything for a shared app shared db model, and to have a user/tenant heirarchy in every app. You can start with each user belonging

It’s really best to design everything for a shared app shared db model, and to have a user/tenant heirarchy in every app. You can start with each user belonging to their own tenant. You can in the future shard the db and/or app by tenant for scalability, you can provide a dedicated instance as required for data residency or whatever.