Welcome!
Well first, if you think folks are doing better than you are with gastric sleeve, think again. The long term results are similar, "failures" (depending on how you define success) are frequent, and the sleeve is not as effective for the metabolic issues of obesity as gastric bypass, esp for type 2 diabetes.
Next, I would strongly recommend that you look at the results for the various stapling type revisions for gastric bypass, of which overstitch is one. I hadn't looked into this for a long time, but did when they first began, and what often happens is that there is some initial weight loss because the patient is on a liquid diet for several weeks, and after that, not much. I don't know specific results for overstitch, but I have no reason to assume that results with this specific devise are any different (I could, of course, be wrong, and as the potential patient it would behoove you to research this and ask LOTS of specific questions before proceeding). Also, last I knew, none of these endoscopic procedures were considered standard of care and I haven't heard of insurance covering them, and last I knew they cost about 10K. That could have changed, again a crucial question for you to nail down. It's possible that you could decide to revise to the DS, which can also be difficult to get covered by insurance depending on what insurance you have, and there is no point in wasting 10K on something that isn't likely to help you long term.
The appeal of the endoscopic procedures is that they are relatively low risk, pretty much available, and it sounds like such a simple solution. Revision to the DS is a big operation, may require travel depending on where you are, has substantial risk and is more expensive if you are the one paying for it. But there is no point in having any procedure that is unlikely to achieve what you want.