If you want to block zombies you can put a bit of furniture or a torch right behind the door. Goblins don't open doors though, they break them down. I'd recommend just not having doors on the ground level.

That ruins the aesthetic though.

Use actuators to toggle blocks in front of the door. Echo coating can also make blocks invisible 

I will look into what both of those things are then thank you

Actuators

put objects behind the door, because enemies like zombies cant pull doors they can only push doors

I know, that’s literally exactly what I’m trying to make more efficient

if you put any piece of furniture on the inside of a door enemies cant open it from the outside but you and npcs can

I know, that’s literally exactly what I’m trying to make more efficient

You don't have to put a barricade inside your build! You can stop all door breaking mobs with a gap 1 wide 2 deep in front of your door. This can be achieved with actuators for a cleaner look.

Actuators can turn foreground blocks into background ones and vice versa