Honestly, how big your application needs to be to outgrow SQLite? If you can serve X customers from one server with SQLite, good for you. If you need to serve more people, you should be in a position to afford migration to something more complicated and good for you too. I don’t see a problem here. Let’s start small with the right tools and don’t fall in the premature optimization trap. You don’t need DB cluster, Kubernetes and other fancy stuff when you start your project.