IEM: IE200. Killed my urge to buy any other IEMs

Can: Sennheiser Momentum 3. Got it for dirt cheap and could be used almost anywhere (compared to my wired options).

I’m German, English is my second language, and there isn’t really a German phrase for this concep

There is. It’s “Leica”

My wife loves her APM and thinks my K612 sucks.

Most friends of mine have similar opinion after several tries.

I couldn’t disagree more, but I do think their opinions are valid to them. People have different taste, and open back headphones sound might not be enjoyable to everyone.