> Any time someone says ‘this works for small workloads’ I hear, ‘we’ll eventually have to migrate this’.

Personally I aim to develop with future migrations in mind. Certain abstractions are worth it. Put an interface around a cacher, db store etc. Day to day dev overheads is low, but your future self will thank you should you need to migratw away.

Sure this isn't always possible, but do it as much as possible.