Where should I put config beans with a Spring Modulith project?

Question

In a Spring Boot project using Spring Modulith to structure the application.

When I add a subdir "config" with a bean definition, the app refuses to start. The file looks like this:

@Configuration
@EnableWebFluxSecurity
public class WebSecurityConfig {

  @Bean
  public SecurityWebFilterChain registerAuthenticationFilter(
    ServerHttpSecurity httpSecurity) {
  ....

I get error when starting the app:

Error creating bean with name ...
   Unsatisfied dependency expressed through method 'setSecurityWebFilterChains' parameter 0: 
   Error creating bean with name 'registerAuthenticationFilter' defined in class path resource 
    Failed to instantiate [org.springframework.security.web.server.SecurityWebFilterChain]: Illegal arguments to factory method
    'registerAuthenticationFilter'; args: org.springframework.security.config.annotation.web.reactive.ServerHttpSecurityConfiguration$ContextAwareServerHttpSecurity@284bdeed
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredMethodElement.resolveMethodArguments(AutowiredAnnotationBeanPostProcessor.java:875) ~

When I put the file with the config bean in the root directory, then it the apps starts just fine.

The project strucuture looks like this:

/root
  application.java 
  /config
     WebSecurityConfig.java  <- this one is the problem
  /moduleA
  /moduleB

But when I have more config beans, and a lot of them are cross-cutting, I would like to put them in a own config directory. This seem to contradict the normal modulith convention. How do I organize the config beans when using Spring Modulith?

It is Java 20 and Spring Boot 3.1.4