Good Player Input/Controller Design

Hi everyone,

Just wondering if someone can point me in the right direction or educate me on what exactly would be a good player input controller.

My question is something like, if I were making an RTS with a lot of potential keyboard commands, how do I set up the input controller? Do I have my Update function track each potential command and fire an event if so? For example :

 private void Update()
     {
         if (Input.GetMouseButtonDown(0))
         {
             if (Left_MouseButton_Press != null)
                 Left_MouseButton_Press();
         }
         if (Input.GetMouseButton(0))
         {
             if (Left_MouseButton_Pressed != null)
                 Left_MouseButton_Pressed();
         }
   
                 // etc.

It just seems after some point, that's a lot to track during a single frame. Would I have to separate such a design by command behavior? As in, have multiple scripts with that above design but only tracking a few events each.

Thanks for any and all help and time, stay safe everyone.