Hi and welcome!
Dr. Ayoola in Denton, TX has begun doing RNY to DS revisions. I don't know how many he's done. He definitely has a good reputation for the DS, and it would be up to you to decide whether or not his RNY to DS revision experience is acceptable to you. But he's the closest to you for sure, no matter where in TX you are.
we are seeing more and more people all the time with failed RNY seeking revisions. Of course, the fact that RNY was done so much more than any other operation for so long has something to do with this, but also people are finally realizing that there is a significant failure rate for this operation (30% failure rate if you assume that "success" equals losing 50% of your excess weight, which isn't that great a result IMHO) and that revision is actually possible. So you are not alone, and hopefully more experienced Ds surgeons will take on these complex revisions in the future, but for now there are very few surgeons to chose from.