veganwithabeef - ZeroWater jug + remineralise yourself with 100mg/L sodium bicarbonate (or potassium bicarbonate).
My water TDS is around 180ppm (tds meter) hardness is 310ppm (drop kit).
For my usage, with the Lelit Elizabeth, 2 coffees a day a filter lasts me approx 10 months.
I’ve been using this formula for almost 5 years, and my Elizabeth is good as new.
A ZeroWater jug + extra four filters will set you back approx. £70 (shop around) if memory does not fail me.
https://coffeetime.freeflarum.com/d/568-zero-water-jugs/147