Here is a proposal based on a quick overview of the code with, I hope, enough explanations so that it makes sense.
Spring Boot adapter
keycloak-spring-boot-adapter is the code that holds the auto-configuration as far as I can see so it would be nicer to name it that way. I'd suggest
keycloack-spring-boot-autoconfigure but it's really not important.
KeycloakSpringBootConfiguration should be renamed to
What is important is that rather than taking dependencies and patching them in a shaded jar at that level, you should take that decision in the starter, leaving all that business out of the autoconfigure module. Here is what I suggests: