[masraum]

There are a couple/few dishwashers that have built in water softeners (you add salt to the d/w). Bosch makes at least one.
https://www.bosch-home.com/us/productslist/dishwashers?f_bvc_mo=bvc_bvc_bema&f_highlights_ma=water_softener

Also, there's at least one manufacturer that makes detergent for hard water. I don't know if those would help the internals of the d/w.

https://www.finishdishwashing.com/products/detergents/quantum-hard-water-detergent/22-regular/
https://www.finishdishwashing.com/products/booster-agent/14-oz/
https://www.finishdishwashing.com/products/rinse-aids/jet-dry-hard-water/8-45/