My situation is a little different (GERD and hiatal hernia, but sleeve seems okay) but here is what I would suggest based on what I have learned trying to understand my problems.
It might be worth getting a second opinion from a surgeon in a different practice who is willing to look at your upper GI imaging and tell you if they think the sleeve looks properly shaped or not. I have been reading this doctor's webpage where he talks about how, in some cases, a misshapen gastric sleeve can aggravate GERD: https://houstonsleevesurgeon.com/category/acid-reflux-and-heartburn/
If you are having significant GERD, you should probably get on meds for that and see if that is enough to control it. When I was reading about this, I did see one study that talked about how, for some post-sleeve patients, the GERD gets better after about 3 years or so because your stomach becomes more "compliant' by that point (and then there is not as much pressure in the sleeve to push the acid up), so if the GERD is controllable with meds, you could try waiting it out and see if it gets better. If it doesn't get better, or if it is not responding to the meds. then you have to decide if you want to get an RNY, or if you want to try the Linx, or possibly ask your doctor about this new procedure I recently learned that some doctors are trying for those of us with sleeves who are having GERD: https://www.sciencedirect.com/science/article/abs/pii/S000296102030814X