Water and minerals
Water, the first ingredient in your coffee
Coffee is 88% to 98% water depending on the brewing method. The bean brings the story; the water decides what makes it into the cup.
Its mineral composition selects what it expresses. Magnesium carries brightness and aromatic complexity, calcium carries body and texture. Bicarbonate, on the other hand, neutralises the very acids you are looking for: water that is too hard gives dull cups, whatever the coffee.
Two levers, two families of products:
Filter out what gets in the way: chlorine, metals from the pipes, excess limescale.
Add what is missing: calcium, magnesium and alkalinity, dosed on purpose.
One clears the ground, the other composes it. Most brews benefit from both.