I have hard water as well and like this one: https://a.co/d/7C7OYlR which I've used for last 10 months so far; fairly easy to clean the bottom where residue tries to build up
I only use it for boiling though; I use this pot for brewing: https://a.co/d/fTXsavt
I've ran GNOME for years until this month. Something randomly broke and then on fresh install the dark theme wasn't working correctly. Switched to KDE and everything looks and works perfectly. Think I'll hang out here for the foreseeable future.