I think the general adversity against this specialized configurations is that they often tend to be fairly limited/rigid in what they can do, and if you want to customize anything you have to rewrite the whole thing. They effectively lock you into one black box of doing things, and getting out of it can be very painful.
Spring is written by a committee of junior developers trying to implement the ideas from a committee of slightly less junior developers. Which is to say it's a huge unintelligible mess. As the other commenter attest, it works really well if you need the one thing it does - unfortunately the moment you need something slightly different you are forced to dig deep into the insane internals and it is a disaster. This moment comes very quickly too in every project because it was written by people with no experience in real projects.
Please use the facilities of the framework for debugging any lifecycle issues. I was surprised when I found out that people did not use `--debug` for example or enabled logging of application startup events.
If you prefer GUI, Intellij even has a Spring Debugger: https://www.jetbrains.com/help/idea/spring-debugger.html
I stopped using Spring Debugger because for some inexplicable reason enabling it makes breaking at the breakpoint take minutes instead of seconds. For quite a while I didn't realize this was the problem, as IntelliJ started having it turned on by default at some point.
Spring boot just provides what they think are reasonable defaults and you provide some specifics.
You can always inject your own implementation if needed right?