Thanks for writing in with your questions.
The number on thing you can do to improve your performance on these long mountain objectives if to build a big aerobic base with time on your feet. As soon as weather/conditions permit I’d recommend starting to run and build to longer mixed/run hikes on hilly or even better mountain terrain. Provided that you technical skills are up to snuff for the first climb, that is.
If not then you need to get more time on goal similar technical terrain.
Some of those skill building days can also be combined with long duration Z1-2 tie on your feet. But, really, time moving on your feet, especially over rough ground is going to pay off best for these goals. You can never have too much aerobic base.