Black locust and osage orange are the most rot resistant you can find pretty much. I think you are in texas right, so they probably don’t grow as big as they do farther north. I’ve seen a couple 3’ osage in Tennessee and black locusts get pretty big up north. Other woods that are also fairly rot resistant are black cherry, black walnut, mulberry, honey locust. If you’re in texas mesquite is supposed to be pretty good too.