BluCig, if you are a singer, you probably don't want to smoke or vape, just because doing nothing is better than using a nicotine product. That said, my voice has returned to usability since I quit smoking and still vaped. My lungs cleared up, I can exhale all the way down to nothing and I don't have that congested feeling that I used to get in the last part of the exhale. I can hit clear high notes that used to only rasp and break up when I tried. Smoking is a real problem for singers. I don't see
vaping that way.
If you need to vape because the alternative is going back to cigarettes, then by all means vape! You will probably find that your voice improves and your breathing is fuller and deeper when you need it.
Drink lots of water based liquids when you vape. PG especially dehydrates your mouth, but a sip of water will counteract it. Try it and see and then make your decision. It's tough to quit smoking, but with vaping, you can taper downwards in nicotine content until you get to zero. Past that point, vaping is mostly just reinforcement for the hand to mouth habit that we all have as former smokers.
Remember that it takes 9 months or more for your lungs to completely recover from smoking. Some of the symptoms you experience until then may be after effects of smoking and not artifacts caused by vaping. Don't blame it on vaping unless you stop for a sufficient length of time and a particular symptom goes away and starts back when you vape again. At that point, you can change mixes and try VG liquids to see if PG caused your problem. A small number of people have PG allergies.