Stem shorter than 60mm

More than you think, you'll feel very different on a bicycle after 50 miles riding non stop.

Can you elaborate more please? I can surely understand the basic principle, of course a continuos 50 miles ride puts the body under additional stress and fatigue, but then, if a good custom frame can mitigate this and make the ride more enjoyable and effective, shouldn't this also be true when scaling down to a more relaxed day to day commute? You know, it's difficult to say: "Ok let's go OTP" when pretty much everyone here on the forum continuously praises steel and custom builds, you can't deny it creates a bit of confusion in who like me is trying to make an properly informed decision. But I'm happy if someone can explain me in which scenario a custom frame will be worse than an OTP (forget about the cost for a moment).

In regards to mudguards, bottle cages, brakes and so forth, I see your point and that's why I kind of did my homework already and thought carefully about what I want and what I don't as I always do. I'm pretty good at being geeky when it comes to buy something new, I try to dive and understand as much as I can, which is also why I'm keeping making questions.

Also, whether it's a good trait of my personality or not (most would say not), unfortunately despite my age I'm still compulsive on certain things and when I put in my head that I want to do something I have to do it the way I want or close enough and that's why I'm insisting on this. It feels like you want to buy a Porsche but everyone tells you not to because they think it's not for you rather than tell you maybe to buy a Carrera instead of a GT2 instead.