Instead of the list format of the sack, could the Item preview tooltip of the bundle be used here?
mostly asking as the 9 slot list hides after five different items.

So having it display like this would help a lot visually

No since shulkers don't and I don't want to add them to shulkers as I've already pretty much that but it uses quarks classes as quark adds these to shulkers too so it makes sense there.