The problem with green tea, for me, is that it causes kidney stones
I used to drink a lot, and after I cut it out (and started taking magnesium) stones mostly went away.
It also agitates GERD/acid reflux, in people who have that problem.
Is it green tea causing the stones or hard water?
People who live where there’s lots of limestone seem to get kidney stones more than people who live in the lowlands or on the coast.
IDK but it’s a possibility.
People who drink beer have less kidney stones.