Interesting.

I had a hiatus hernia diaphragm repair way back when I was 27. I had a faulty valve at the bottom of my oesophagus where it meets the stomach. Main symptom of many was reflux.

That's maybe why I thought of reflux with your other problems.

I drank dandelion tea for years. Most people I know can't stand it, but I don't mind the fact it tastes a little like coffee and it's nutty.

I tend to live on the cliff face of anxiety, always have, so I am pretty careful how much caffeine I consume.

I loathe the taste of green tea for some reason but occasionally I drink it. That may be because I drank copious amounts of "proper" green tea when on trips to Japan years and years ago. I can still taste the earthy pungent aroma just thinking about it.

I drink 2 cups of coffee every morning. No caffeine after 10am. Strict rules I set myself.
I tend to wake up and start reading medical journals so I need the coffee for that.

I love tea. I buy a very good local tea that's low in tannin and caffeine and I have one of those mid afternoon. Sometimes I replace my morning coffee with tea but use something stronger, like a breakfast tea or an earl grey or something nice.

If I stop the coffee altogether I get headaches. That was my thought about you in the beginning and if you can substitute one of the coffees for green tea so that you don't end up getting withdrawal headache.

You don't sound as if you drink much though. I've heard of people who consume 10 or more a day. yikes.

another thought... I wonder if it's the Tannin that is the problem for you. Just thinking.