I would say you are doing very commendably well. You can also find a doctor who issues home kits to detect sleep apnea. Also, a Holter monitor worn for maybe two nights...and days...would reveal variations in heart rate and rhythm, and if they rise and fall grossly during the night hours it may signify either REM sleep, which is ideal and desirable, or a heart under duress due to hypoxia....which means apnea. A RESMED 11 Airsense 'Autoset' would titrate you automatically and you would do well...PROVIDED...that you don't have significant CA..central apnea.
You are doing all the right things. Try to get your BMI down below 28 if possible, so great progress there, no snacking after about the time that is three hours prior to sack time, so about 1900 for many of us, caffeine and alcohol are probably okay occasionally, but early in the day, not after 1500 hrs for the caffeine.
Incidentally, my cardio asked me what my neck circumference is/was. I thought it odd, but when I got his formal diagnosis of paroxysmal AF, I began an intensive study to determine what my options and prognosis were likely to be, and learned that, statistically across patients, a neck girth of 17" and up is highly correlated with OSA. Mine never gets above 16", but I still have a formally assessed diagnosis of 'severe sleep apnea.'