There was somebody who was using one of the various sqlite replication tools to do multi-instance pocketbase. I can't remember if it was LiteFS or dqlite or something else, but I remember it scaling pretty well. The majority of applications aren't going to outgrow single-instance sqlite though.
Also, you can do programmatic setup of tables with migrations: https://pocketbase.io/docs/go-migrations/ (also available in JS). I can't remember if pocketbase will automatically write migrations to disk for you or if there's a flag you need to turn on, but you can generate those migrations on a local instance, commit them to VCS, deploy them somewhere, and either run a command to run the migrations or turn on auto-migrate (which does what you'd expect).
Also, you can do programmatic setup of tables with migrations: https://pocketbase.io/docs/go-migrations/ (also available in JS). I can't remember if pocketbase will automatically write migrations to disk for you or if there's a flag you need to turn on, but you can generate those migrations on a local instance, commit them to VCS, deploy them somewhere, and either run a command to run the migrations or turn on auto-migrate (which does what you'd expect).