This is an area that isn't well understood. Just a few things that experts in this area have told me, as I have also had abnormal motility on testing.
"...in general, patients with active reflux disease often have other problems with relaxation of the esophageal sphincter (that "hypotensive LES"), and various other motility problems of the esophagus. These findings may or may not be a direct result of reflux-related injury. In some cases, abnormal esophageal motility results from acid-related injury, and in other cases, reflux may we worsened by abnormal motility. It can be a vicious cycle. And one must remember that the motility test results are a snapshot from the time of the test, and that actual function can fluctuate over time. There is much we still do not understand about esophageal motility, and how to promote normal esophageal motility. "
"...Furthermore, severe IEM (90% or more non-transmitted/hypotensive contractions) make surgeons pause before doing anti-reflux procedures, and many will offer a partial wrap rather than a full 360 degree Nissens’ because they’re afraid the patient will be more likely to get difficulty swallowing after surgery if they have severe IEM."