For my project, I didn’t need any doorways as the game is set outdoors. I did consider an arch, but that’s a nice to have, not need to have object. That said, stairs act as a doorway onto platforms, so that’s what I have here.
I added some detail to the front faces, making them look bumpy like rough brickwork, but nothing to the sides as it is unnecessary.
I did not make the textures, they are from textures.com. It is within the licensing to share an image of my work in progress using the textures.