Tea tastes harsh and drying whatever I brew
Every tea lands rough and mouth-drying, the puckering feeling rather than a bitter taste, at times and temperatures that used to work.
Likely cause
Hard water is a common cause and easy to miss, because it does the same thing in every cup. It raises the drying feeling specifically: if your tea is bitter rather than drying, hardness is probably not the culprit.
Test it at your sink
Rub a little plain bar soap between wet hands, not washing-up liquid, which is made to lather in hard water anyway. Real hardness gives you a thin curdled scum instead of a proper lather.
What to change
Brew the same tea with filtered or bottled low-mineral water and compare side by side.