For me, avoiding high histamine foods as well as histamine liberators had helped tremendously.
The theory:
Anti-histamines like Benadryl make you sleepy by blocking histamine.
Well, instead of blocking the histamine, get rid of it in the first place by avoiding histamine foods (for example aged or preserved meats).
The brain histamine in your neurons is primarily synthesized from an amino acid. The histamine levels in neurons are different than the levels in mast cells.
There are a lot of degrees of hand waving in your theory that don’t work.
I definitely haven't looked into the underlying models of histamine to see how things work.
My observation is that, when I avoid histamine related foods, I sleep longer and fall asleep faster. The naive model is what led me to try that. But I totally acknowledge that there's likely way more at play under the hood. And I would like to know more about why this works! Or, at least why it works for me.
Thank you for pointing out the complexity of the underlying mechanism.