”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.
Doesn't seem to be anywhere close to the potency of MAO inhibition used in psychiatric or entheogenic contexts. I'd be reluctant to attribute too many noticable effects to them.