How to create the class instances dynamically and call the implementation

I have various interfaces and I need to be able to call them. Here is the base class:

public class MyActorBase<TChild>: ActorBase where TChild : MyActorBase<TChild>
{
    public MyActorBase()
    {
       var actors =  ChildClass
           .GetInterfaces()
           .Where(i => i.IsGenericType && i.GetGenericTypeDefinition() == typeof(IActorMessageHandler<>))
           .Select(x=> (arguments: x.GetGenericArguments(), definition: x))
           .ToImmutableList();

       if (actors.Any())
       {
           var ty = actors.First();
           var obj = Activator.CreateInstance(ty.definition, true);

           // how to call method implementation
       }

    }

    protected sealed override bool Receive(object message) => false;
    private Type ChildClass => ((this as TChild)?? new object()).GetType();
}


public interface IActorMessageHandler<in T>
{
    Task Handle(T msg);
}

I want that any class that implements the IActorMessageHandler, i should be able to call its method Handle(T msg). so while I was able to instantiate it (considering that I'm not using any dependency injection) how can I call the method in the most efficient way?

Is there any alternate to reflection?