Coffee is around 98% water so good water is essential if you want good coffee and all water isn't equal. I grew up in rural Indiana drinking well water. I have lovely memories of hot Summer days and my Dad spraying me down with the garden hose in the back yard. I can still recall the cold, crisp water from that hose. Have you had hose water recently? That's some nasty stuff. Coffee brewed with well water tastes bad but not to the people who drink well water everyday.
The SCAA has water standards for coffee brewing. Here's the details if you like going down rabbit holes. Have fun delving into that. I don't have the available bandwidth.
Chicago water makes pretty legit coffee straight outa the tap but I can taste the chlorine. I'm not as fussy as my wife likes to say, but I can taste the difference (especially chlorine) from tap water and water put through one of these. It's a simple cost effective solution. Like all things, you can easily go overboard, don't.
Here are some simple rules:
1. Start with fresh, cold water, hot water has been concentrating/hardening in the water heater.
2. Get rid of chlorine either by filtering (see above) or simply set the water out overnight and evaporation will take care of the chlorine.
3. Heat to between 195 and 204 degrees. (explore)
4. Don't reboil-see #1 above.
As always, enjoy the journey, play around and find what works for you. And for god's sake don't over analyze it.