Really? I'm confused to this thread discussion. Let me try to analyse.
Chest should be:
"regular" storage = false, Minecraft storages contained more space and beyond one meter cubed because you could store
banners,
boats,
minecart with mount,
beds,
buckets contained or uncontained (it's size was debatable),
ridiculous size of Enderdragon Head ,
End Crystal,
doors. True, when Shulker Box/Inventory/Other Chest contained Chest or even dropped Chest.
Chest could be (or similar to):
4d pocket storage = functioning similarly like a
small portal
Trade In/Out (interacts spacehammer) = true, when Steve/Alex being able to be transported with things inside without carrying/showing/handling their resources.
.
Inventory could be (or similar to):
Magic Satchel = functioning similarly like a crafting
"in which the user can make anything they wish" inside inventory
"Even if the thing doesn't exist.". Inventory is like virtual interface version of
"The magic satchel..." (nerfed version).
Requip = functioning similarly like a
item switching and the "belt" is a
"store items in a pocket dimension so they can easily summon it at any time, even during battle."
Mini pocket dimensions = since Shulker Box is a dimensional storage itself, and Chest and Inventory could carry multiple Shulker Boxes so Chest and Inventory must be Mini pocket dimensions. Unlike basic "rpg" volume storing magic satchel, Mini Pocket dimensions contained smaller dimensions like Shulker Boxes.
.
Note: Shulker Boxes, Chest and Inventory be same space sizes but their functions were different.
Note2: There's evidence they can create
mini pocket dimensions: it happen when Steve/Alex placed (not store) Chests and when they crafted Shulker Boxes since Chest couldn't contained items like Shulker Box and when Shulker Box/Inventory/Other Chest contained Chest.
Note3: When Shulker Box/Inventory/Other Chest contained Chest there was no storage dimension or space just "regular" chest. When Chest was placed it turn to mini pocket dimensions as dimensional storage.
Note3: This is just creating a dimensional storages assuming they don't used it on the battle because simple there's no function nor ability to "suck in" coming attacks or effects, nullifying them and releasing them later. But Steve/Alex has natural ability to "suck in" dropped items itself.
Note4: It's mini pocket dimensions because
they could contained life. example: Bucket of Fish. It was now official :^D
.
So yeah Chest/Shulker Box/Inventory was mixed
Dimensional_Storage confirmed! That was complicated d*** (oops)