Try cloudron.io. It's exactly what you are looking for wrt app updates. You can make custom apps and not just from the store. All apps are on a single server as

Try cloudron.io. It's exactly what you are looking for wrt app updates. You can make custom apps and not just from the store. All apps are on a single server as well (and not about "scale") Disclaimer: managed cloudron customer (I have not used the selfhosted option).