https://theprepared.com/bug-out-bags/reviews/best-bug-out-bag-backpack/
Picking the best survival backpack is often more challenging than picking most of the stuff that goes inside the bag.
Even when you set aside personal preferences like fit and color, there are tons of considerations that matter in an emergency context: what kind of organizational layout is best for common gear, how well does a bag balance blending in vs. tactical features, weight vs. durability, and so on.
More: Bug out bag checklist and first aid kit checklist