Sounds like you have alot to learn about even basic MVC in Java. Try what you are talking about in Springboot? Go ahead. Show me a RUNNING EXAMPLE that is SIMPLER that just AUTOWIRING.

Once you create that constructor, you NOW have to define the bean and automap it to the RequestMappingHandlerMapping

You just overcomplicated the entire thing simply so you dont have to use autowire.

This was your clue. Get it.