Do not worry, so called "the best" ending is not considered as such by many people, me included.Didn't expect such an elaborated reply, thanks for all the infos !
And interestingly enough, I actually used the walkthrough since week 3 cause yeah, some choices were kinda... 'weird', well, to me, but it's the walkthrough that lets me open every path hahaha, that's why I asked here, thought it was fishy.
Well, before you replied, I found out pretty fast the Amy path would clash with Melody, so I re-loaded a save and ended things with her instead.
But otherwise, yeah, Izzy (wanted to end it next time I see her) and Becca (this one was going to be tougher... she really is a nice girl) are still a thing, so, glad to know I fucked up already ! Still isn't clear though, started fooling around a bit before the Melody path was even becoming something... oh well.
Anyway, thanks again !
Since the second to best is much more homely and has that human dimension.