If you have to go up you must come down- the king of descenders is the Colnago C50. I still thinks its the best bike around, reliability is awesome, Ive raced the paris roubaix course on mine aswell.
If you want to spend less and have a pure climber the scott addict is apparently good, and super light. Top end time, look, pinarello, cannondale also very good- not many bad bikes around these days.
If you went for new dura ace you could go compact with a range of cassettes from 28-11 – not far off a triple.
i would avoid cervelo- over rated, expensive and toe overlap.
I’d take a triple to the alps, i have done on my previous trips. Saves on patella tendonitis and associated knee problems.