> It sounds like you may be suffering from the Paradox of Choice when it comes to the broad Java ecosystem(s). For new projects, just pretend nothing exists except Spring Boot and use annotation/java config for dependency management.
Spring Boot is passable, as long as what you are trying to do fits within what you're allowed to do and you don't have to dig into the internals too much. Regular Spring is painful, attempting to migrate a project that's been around for close to a decade from Spring to Spring Boot without a rewrite is even worse, especially if it is stuck on an older version of Spring, even worse if you need to go from JDK 8 to JDK 11+.
The complexity of Spring and Spring Boot itself is pretty considerable. I wouldn't scoff at anyone using something like Dropwizard for comparatively smaller projects, as I did recently: https://blog.kronis.dev/tutorials/2-4-pidgeot-a-system-for-m...
In a limited set of circumstances it can be useful to opt for something simpler, that's built on a bunch of other boring, mostly "standard" or at least idiomatic packages. Some might advocate for Quarkus, others for the likes of Vert.X - both are interesting and pretty usable, but perhaps it's a bit too early for either of those. For those interested, ktor might also be worth an exploratory look in non-prod projects (if you like Kotlin too).
There is something to also be said about the likes of Ruby and Ruby on Rails, or PHP and Laravel, or .NET and ASP.NET, or maybe Python and Django - sometimes having fewer options can also make you more productive, especially if a lot of ecosystem is grown around those "main" solutions. Perhaps that's an argument in the favor of Spring Boot.