My 16-month theanine self-experiment

”I’ve long found that tea makes me much less nervous than coffee, even with equal caffeine.”

Well, of course you are less nervous when you avoid taking coffee: it contains a LOT of beta-carbolines which act as MAO-A inhibitors. MAO-A inhibition directly prevents adrenalines from being inactivated by oxidation.

In spite of the confidence you're stating this with, it sounds like a serious over-simplification of a very complex dynamic.

Occam’s razor. These compounds do exactly what I’ve described, which directly increases feelings of anxiety.