I have too many packs, if such a concept exists.
My old Karrimor Alpiniste still does the job, perhaps 55l plus xtendable top and side pockets can be added.
A POD cragsack at about 40l for, er , cragging.
POD teardrop for climbing long routes, or winter days out.
Osprey 38l pack for summer walks coz me back was getting too sweaty and causing problems, currently using in Austria and it is such a good carry, and no sweaty back !
Karrimor kimsac for going very light, great minimal kit.
Berghaus cyclops Roc bought from this forum, vintage kit, still lne of the very best back systems and a beast for big loads.
Two North face day sacs, one permanent climbing wall bag, one just handy for carting small loads 20l around, has laptop sleeve etc.
They all do specific jobs well, accumulated over a few decades, and I love them all, so would hate to have to choose one over the rest.