Maybe. I'm not convinced. There is some correlation between obesity and sleep apnea, but skinny people can develop sleep apnea just as easily as fat people. It is very difficult to lose weight (and very easy to gain weight) once you do develop sleep apnea for a variety of reasons, so the causal relationship might even be reversed.
That being said, if you suffer from OSA and have a lot of fat on your chest and around your airway, losing some of that fat might help. Maybe GLP-1 drugs can do that in spite of OSA.
"Massive"? The intervention group went from a mean AHI of 49 to a mean AHI of 37. While the control group went from 49 to 43. It's something, but it's still very much in the "severe" category, and I wouldn't call it "massive".
Proper CPAP usage would reduce this group's AHI to <2 events/hour.