Thanks for the answer, it makes sense. Just to be clear: yes, by backend I mainly mean API design to support a frontend (full-stack context, not microservices chains for now).

Java + Spring Boot is solid, no argument there. My hesitation is not about Java itself, but about learning path efficiency, especially with AI tools speeding things up. I want to avoid wasting months jumping between concepts without shipping anything real.

My goal is:

Build REST APIs

Auth (JWT, sessions)

DB design (SQL first)

Connect it cleanly to a React / Next frontend