[mulrian]

This. Might not be hip and trendy, but we've been using this stack (just with React on the frontend) and it's probably the best that I've ever worked with.

Anyone who knows Java/Kotlin will have experience with Spring Boot so it's easy to find good people. The whole platform is as mature as it gets at this point and the docs/questions cover pretty much everything.

It's really easy to get started when working on smaller projects, but you can also easily scale and integrate loads of other technologies if/when you need to. You might not need a complex caching layer, monitoring, metrics etc when you're starting out, but you know you can add it in if needed.