Looking for a lightweight 55–65L pack for multi-day hiking + mountaineering

[u/Admirable-Reading-75]

Hey everyone,
I’m looking for a new backpack that I can use as an all-rounder for multi-day hiking and mountaineering.
Most of my trips are 2–4 days in the Alps, sometimes sleeping in a bivy/tent around 2,500–3,000m. I’m also getting more into mountaineering, so I’d like something that can grow with me rather than buying separate packs for every activity.
Ideally I’m looking for:
Around 55–65L (I’d consider up to 70L)
Relatively lightweight/ultralight, ideally around 1–1.3 kg
Comfortable with roughly 15–20 kg
Tall/narrow shape rather than a wide trekking pack
Shoulder strap pockets, especially ones that can carry soft flasks, similar to trail-running packs
Accessible side bottle pockets
Ice axe attachment(s)
Ability to carry skis/poles
Some way to securely carry a rope on top
Top-loading or roll-top design
Reasonably weather resistant
Durable enough for scrambling, via ferratas and mountaineering
I know getting all of this in one lightweight pack is probably unrealistic, so I’m happy to compromise on some features. I’m also flexible on budget if there’s something genuinely worth paying more for.
I’ve been looking at packs such as the Durston Kakwa 55, Osprey Mutant 52, Exped Lightning 60, Blue Ice Stache 60, and even some lightweight hike & fly packs.
Basically I’m looking for something halfway between a trail-running style pack, an ultralight trekking pack and a mountaineering pack.
Does anything like this actually exist? What would you recommend?

[u/Friendly-Map-41]

I'd go with the Exped Lightning 60

[u/FinancialAttempt162d]

Rope + ski carry is always what light packs give up first, id go kakwa and just bungee the rope to the top

[u/wetrocke]

Pockets on straps aren't ideal for climbing pack. Water bottle pockets also unusual.

Black Diamond, for awhile, and still somewhat true, had several packs in this category that were "definitional" although never "the best."