I have several backpacks for longer tours.
MILLET PEUTEREY 50 is a mountaineering one, it carries very well, but I miss the side pockets; it doesn't need a rain cover because it has waterproof zips, at least that's what they say.
I don't know how the ice axe attachment is, but they will explain it well in Iglu Sport.
My wife has a VAUDE TOUR 40, which seems ideal to me for summer even multi-day tours; the backrest is very spaced from the back, full of pockets, rain cover, lightweight.