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.