Hello, fellow PG allergy warrior!
I am SO GLAD you brought up the theater smoke thing because I recently ended up bowing out of a family outing because I was told theater fog would be present. I won't get into the details because this is about YOU, but the whole situation was really aggravating on SO MANY LEVELS. It's amazing how many different types of things contain propylene glycol... from food to body products to medication and theater smoke... it's hard to avoid! People joke sometimes and say things like, "Man, I bet you're even allergic to soap!".... thinking they're being funny and extreme, but their face always drops when I tell them they're accurate. I'm very grateful for this online community because most people just do not get it. How could they?
For steroid ointments, I had success with Desoximetasone. I haven't used it in over a year because I hate paying for expensive medications and people's skin can become dependent on topical steroids and thin the skin... not good. But if it must be used, what else can you do? I've tried oral steroids (Prednisone and between how bloated it made me and the side effects I read about, like, psychotic breakdowns... I was like, no thank you).
As far as tips go, it sounds like you're on the right track. Reading ingredient labels is huge as is doing your research. The most aggravating thing about propylene glycol is that is goes by many names! Here's a list of alternate names. Definitely stay away from modified food starch... read more about that here. Many people with PG allergy will tell you to avoid propanediol, so I looked into it. I also got some doctors involved and you can read about that here. This is also a little list of other items to watch out for.
I hope this helps! Best of luck on your journey!