I made a planetoid Minecraft demo back in the day, but I left the planet as a cube. Each cube had a defined gravity direction, so you could rig it so that no matter what face you were on, gravity pointed "down". Having gravity be a customizable per cube allowed for cool things like having the center of the planet have reversed gravity, so if you dug too deep you'd find a cavern and could walk on the inner surface of the planet , effectively upside down. Or you could have two planets near each other and build upwards until you entered the others gravity well. I also added portals, so you could even jump through a portal fast enough to get thrown up to a neighbouring planet.

Obligatory awkward demo: https://youtu.be/PDZGzL4GRF0?si=K9vfMhbcg5Vvd1_A