Compact Machines Mod 1.16.4/1.12.2/1.11.2/1.10.2 (Factory in One Block)

Compact Machines mod adds blocks-rooms to Minecraft, which are larger inside than outside. You can navigate to it using a special tool. In addition, these rooms can interact with the outside world through airlocks that allow objects and liquids to pass through, combining this mod with Applied Energistics and other addons.

You can build your own factory inside the room, it will interact with the outside world, moreover, it takes only 1 block, and to maintain it you can climb inside.