If you want to use Java/Spring Boot, I would start with Bootify.io - it'll save quite some time while adding only code that you require for your project.
So far the really interesting stuff seems to be missing, and isn't really in sight either. I would go with low code tools (JHispter, Bootify.io) and continue from there, for now.
Recently there is a trend back from SPA to server side rendering to avoid complexity, which isn't needed for most kind of apps. Htmx is a good addition in this scenario, which describes ajax calls as html attributes. You may have a look at bootify.io for generating such an application setup.
Every language has it's pros and cons, Java has some overhead here and there but very mature and lots of libraries.
Hello,
I've build a tool for prototyping your Spring Boot app with your custom entities and REST API, if needed. Schema generation with Hibernate or Liquibase. An import of an existing schema as SQL is also available since one week.
What do you think, is it useful for you?
All the best,
Thomas