I created a MyCharacter class derived from Character and IAbilitySystemInterface and implemented the interface.
In a blueprint class that inherits from MyCharacter, I see AbilitySystemComponent in the Components panel, but selecting it doesn’t show any details of AbilitySystemComponent (other components’ details are shown well.)
You created this character via C++? If yes, adjust the UPROPERTY parameters of the Ability System Component and, if it is a private component, add a meta to allow private access (like the camera component)