IME, the PNP is harsh as fuck compared to the many other vapes I've owned/used. I even made a custom GonG (with no plastic in the airpath) which made things better with a bubbler, but did not deliver enough clouds, and the plastic top housing still ended up cracking.
If you have lung problems and want to avoid unnecessary irritation, get a decent plug-in (or a solo for that matter). Do not use anything with plastic in the air-path, use convection vaporizers and always use a bubbler/water of some kind to moisturize the vapor.
Also consider using concentrates, which IME when done at the right temperature are much less harsh than buds, and deliver the results with minimal amounts of vapor being inhaled. Remember, vapor does irritate your airways somewhat, and the less vapor per dose of medication you need to inhale, the better
Hope you can find a good balance and the right vape, let me know if you need any further suggestions!