In my recent hiking trip on the John Muir trail, I limited my pack weight to 10 pounds so that I could cover 25 miles a day.
Some backpacks weigh 4-5 pounds when empty.
Mine weighed 13 ounces. It could have weighed 6 ounces if I gave up a bit of durability.
I used the Zpacks Dyneema X 26 holding 2,600 cubic inches.
Dyneema Gridstop is a heavy duty 4.2 oz/square yard. Each white Dyneema thread can hold over 150 lbs. A secondary ripstop grid is angled at 45 degrees.
I've successfully used Dyneema for my outdoor activities for years.
It's abrasion resistant, puncture resistant, and completely sufficient for supporting typical backpack gear weights.
As I hiked, I watched numerous people struggling with 35-50 pound packs.
My advice - start with an 13 ounce pack and only carry what you'll need. You'll enjoy the experience instead of struggling with every step.
A 13 ounce backpack that's stronger than steel - that's cool.