Recommend Shower Temperature and Filter Products

I would strongly advise you to keep it simple. No european thermomixers - most plumbers can not install them.

Thermo mixers, while expensive, are great. I have them and never have to worry about constantly changing temperature. Not familiar with digital display but I am sure someone makes th m.

Wow, is this a real problem in large apartment buildings? Fluctuating shower temperature!

What neighborhood is this co-op in?

Hanklin, very real. Opening the sink faucet or flushing the toilet can create pressure and resulting temperature changes.

Is this post from the 1980s? By code, you must install either pressure balanced or thermostatic shower valves. Few if any "upscale" brands still sell pressure balanced valves which have been around for decades. I don't know what a "european thermomixer" is, but all or virtually all fixture companies sell thermostatic valves. Digital seems like a bad idea for a plumbing part that may otherwise last for many years, but those exist too.