First of all, I have been diagnosed with OSA many years ago. I have a CPAP machine, a dental mouthpiece to hold my jaw forward when I sleep and finally had the PPP surgery. Now what I am going to tell you now is in no way intended to scare you but in my case was reality. After the surgery the doctor told me to come back in two weeks. When I did I told him that it was a good thing I did not see him last week because I would have killed him (I am serious) and he said that is why he says wait two weeks. I lost 25 lbs in two weeks. I tell people that if the Dr. gives you a choice of living six months or the surgery...enjoy your six months. It was the absolute worse experience of my life. Pain beyond description. My wife would take a popsicle and break it up and let it melt down my throat just to get something into me. It was that bad.
Now afterwards and as far as diving. Until you learn how to deal with the loss of the tissues back there, you will choke at times, get water up into your sinus etc. As far as diving goes, no problems but be aware that you might be more prone to choking and coughing and just plan for it. IOW, keep your reg in and cough through it. I tend to breath through my nose after a while due to wearing the CPAP machine. I have recently determined that some of this is due to improper breathing technique so I do not attribute it to the surgery. BTW, there are many different surgical procedures other than a total removal of the uvala. One doctor described one where there is a needle inserted into the excess tissue area and heated up to burn a hole. After the hole heals it pulls the area tighter.
Good luck, hang in there because it won't last forever. Let us know how it goes.