I'm not sure why people aren't saying Spring Boot, but Spring Boot. Yeah it has heaps of other batteries included, and it doesn't have a built-in admin, but it gives you pretty decent stuff out of the box

Java honestly just does not have this. By the time java collectively decided that being able to spend your time writing your actual product instead of fucking with config shit forever, the age of the monolithic SSR templated backend app were gone. So now most modern things like helidon focus on being microservicey like go, or they have very soft template rendering offerings and don't really do batteries included.

I feel your pain, I myself am working on a react frontend + spring boot backend and fiddling with it to integrate with spring session, security, etc properly was a HUGE pain because neither world knows anything at all about each other. If I did it from scratch I'd just "rails new myapp" and be done already.

Isn't there Thymeleaf that alleviates that?

Forgive me, but thyme leaf is soft compared to ERB and jinja.

How about this? https://github.com/dropwizard/dropwizard

There used to be JHipster, not sure if still around