I too have adult acne, I say I'm in my 50s, going on 15. Sigh. I don't get ingrowns anymore, after switching to DE shaving., thankfully
Everyone's skin conditions are different, so none of us can tell you what to do. You've seen a dermatologist, they can tell you, follow what they say.
There are so many variables and I think lots of randomness as well - everything from products to stress to weather conditions. Thus, I can't isolate and test different things to try to improve the situation. With all that said, it does seem like you use a lot of products. Would you consider not using some of the post-shave products that were not prescribed by your dermatologist, then see if you get any improvement?
Everyone's skin conditions are different, so none of us can tell you what to do. You've seen a dermatologist, they can tell you, follow what they say.
There are so many variables and I think lots of randomness as well - everything from products to stress to weather conditions. Thus, I can't isolate and test different things to try to improve the situation. With all that said, it does seem like you use a lot of products. Would you consider not using some of the post-shave products that were not prescribed by your dermatologist, then see if you get any improvement?