Hi! I am a returning player. Back when I got Minecraft, in 2015, I remember there was an "exploit" that made doors unbreakable by mobs. It required you to place them "open" instead of "closed" how you normaly do. This way, when the door was shut and no one could pass through it, it appeared as open so zombies couldn't break it, due to the fact that when doors were placed they were set to closed by default, so when you actually close it, the game identifies it as open. Does this thing still work?
(I also attached a photo of how the door should look when it is placed)