I suggest making them upgradeable to have more inventory space, possibly 2 new backpacks,

[default] Traveler's backpack.

Then a Nomad's backpack with an extra 18 slots of storage space with double the tank size along with a furnace addition.

Then the Expeditionist's backpack, it could have a full 36 slots of extra space, and 4 times more tank space over the Traveler's backpack.

Recipes could take iron, gold, a chest, furnace, and the previous backpack for the Nomad's backpack, then diamonds, obsidian, glass, chests, and the previous backpack for the Expeditionist's backpack.

https://www.curseforge.com/minecraft/mc-mods/travelers-backpack
Backpack tiers added for forge fabric coming soon

Well, that's good idea for a new mod I could work on. Upgradeability kinda departs from original idea of powerful adventure backpack.

Well, that's good idea for a new mod I could work on. Upgradeability kinda departs from original idea of powerful adventure backpack.

i think that it would be amazing to have it as a new mod if you feel its not true to the original idea, i personally like working up to the powerful things and not getting it on the first go. I would love to see this fulfilled as a new mod.