Nice pack although I would change some things to make it really stand out and be an all time mod ⭐.
-Change control to view pack to Ctrl + E. And toggle that button when exiting out instead of pressing Esc to close menu inside backpack.

-A armor slot for backback in bottom right corner of character. Use keybind Ctrl + E to access pack while on the go.

-Key to view backpack in inventory slot to E and only WHEN player has curser over the slot.

-Ctrl + Right click to place backpacks down.

-Armor packs are lame and mid they aren't going to be used for armor anyway. Only a psychopath would use it and only then is useful for beginning game not late game. I'd just remove it

-Get rid of backpack templates and only make the character use one pack frame if they want to mount a pack to their back. So pretty much place mount first then backpack after in backpack slot.

-Fix crafting with the backpacks. It doesn't make sense it needs 4 netherite ingots thats really expensive. At that point id jsut use shulkers than this mod but I appreciate the early game content. Gold pack should just be a block not 4. And how come iron holds less than gold? Maybe just not have gold at all and just put iron.

-Please minimize slot space in leather, gold and netherite. 1 row, 3 row, 5 row.

The other bags are cool but please remove the templates they are not neccessary.
Other than that, mod will be widely used and popular I think if you implement these so please and thank you 🙏