A brief perspective: I have suffered from intense peeling lips from 2013 to 2018. At a certain point it was impossible to go outside, drink or eat without my lips falling on the ground, and making big repulsive yellow chunks.
I, of course, have seen multiple dermatos, done a biopsy which shown nothing at all.
I lurked a bit this forum a couple or 3 years ago, I've tried countless different creams and protocols, involving not touching anything with my lips for months, straws, soft to extrem diet protocols, etc etc. It sometimes ameliorated things but never enough / never long enough.
I don't know where the forum is now to its health quest, but...
I will make my contribution. From what I have learned, this is not a little one, since I probably am NOT at all the only one touched by this bane.
Let me put this simply: what if, all this time, you have been searching for the wrong causes ? We all (I included) thought it was chemical or something related. This might be, in a few temporary cases, but IMO it is not in most of the cases.
I met this person specialised who informed me that my lower lip was "too protruding". It's a trait I have developped over years so it was not obvious to me. It seems (almost) like the normal me.
I listened to this person, and did lips exercises that she adviced me (she's a profesional). Guess what, it TOTALLY HEALED. Even foods that would amplify this curse is not a threat anymore. Cream became kinda useless.
The problem was in my case MECHANIC. And honestly, I won't dig too deep into it, but lots of things tend to make me think that this problem is in most cases mechanical and not chemical. (just for a pist, it is linked to our tendency to have crooked teeth, needing orthodontic appliances, having retruded chins, hypotonic tongues and chewing muscles...)
Well, yeah, after 5 years of suffering from this s*** and trying countless protocols, I finally had the bigger picture - mecanics involved. To see if it could be your case, just look how big is your lower lip (or upper, I had intense peeling on them both). An objective measure to notice it, is named the "mento-labial fold" (just google it). The more pronounced it is, the more likely your lower lips are over-protuding, thus exposing its weak tissues to the outside world - when they should stay safely inside.
Knowing this, the cure is pretty simple compared to the years of suffering. You got to be serious and regular on your training.
You just have to "eat" your lips, force them inside your mouth, then relax, then repeat. You must not in any case use your "mentalis muscle" (chin muscle). Another exercise is to take a button from a jean/shirt, attach a little string to it with a node, and do resistance training: the button in your mouth between your incisors and your lips, you pull the string with your finger while trying to resist with the force of your lips.
In weeks you will see improvements, in months it will be healed.
Hope this may help somebody in their journey. It really went from number 1 problem to no problem in a matter of weeks. :)
Edit: OFC, keep your lips sealed in resting position. Don't mouthbreath. The training above will help you get a normal lip seal without thinking about it.