Is Sleep Apnea Treatment good for longevity?

Yes — the evidence for this is strong. Obstructive sleep apnea (OSA) treatment is well supported by multiple clinical reviews describing CPAP as the primary evidence-based therapy, along with a systematic review and network meta-analysis of randomized trials finding myofunctional therapy improves sleepiness and sleep quality as an adjunct treatment, though without significant change in the apnea-hypopnea index itself. That's reflected in an evidence score of 76/100 for its role in longevity, drawn from 8 studies, with an estimated impact on longevity rated substantial (89/100).