Caffeine, or coffee? They are very different substances: one is a pure alkaloid with well-defined effects, the other is a concoction of hundreds, possibly thousands of active ingredients.

Most relevantly, coffee contains a relatively large amount of Harmala alkaloids, which are a family of beta-carboline monoamine oxidase inhibitors commonly found in Ayahuasca brews (and named after one of its ingredients, Penganum harmala).

I'm down to just black tea, but a lot of it. Occasional cola as well.

Honestly, I need to ween myself back a bit.

I would say caffeine is easy to quit, but I'm an alcoholic so I understand perfectly. It seems like you don't need it, yet you use it regularly.

Try caffeine pills, they have a cleaner effect with no stomach/intestine troubles. Somewhat easier to quit, too.