Why Player input aways get MissingReferenceException?

I started using PlayerInput yesterday but I've been having some problems like it regarding MissingReferenceException

 protected void Awake()
     {
         manager = GetComponent<P_Manager>();
         
         if(playerInput != null && gameObject != null){
             medoAction = playerInput.actions["medo"];
         }
     }
 
 private void OnEnable(){
                 //works
         medoAction.canceled += ctx => SimpleFreeze();
                 // dont works
         medoAction.canceled += ctx => manager.medo.SimpleFreeze();
 }
 
 private void SimpleFreeze(){
         if(manager.medo != null) manager.medo.SimpleFreeze();
 }

In the example above the code that checks if "manager.medo" is null before running works but the other one doesn't, I know that "manager.medo" is never null but if it doesn't check it accuses as null I would have something I can try to avoid so many "ifs" since i know "manager" or "manager.medo" is never null?

Sorry for bad english.