As title says, and 1.12 if possible. Would have done a PR but got confused by the code determining if one spawned or not.

Surface entrances require fairly significant surface conditions to spawn. They already spawn as much as possible, given those conditions. In future releases (for MC 1.18+) I may revisit the surface entrance logic to clean it up and make it more customizable. But existing versions will not be receiving such an overhaul.

Cool, no problem then. Makes sense