Maybe add an optional Container which can be opened and named. Items can be dropped (rearranged)
in this container. Like such

Local Inventory ( 16,263 / 20,000 )

Behemoth Heavy Miner - 1 Item
------Equipment
-------Trident Power Cell
------Cargo 0/140 cu
Behemoth - 1 Item
140x Apicene ore
Axia Accelerated positron
140x Denic ore
Ragnarok MkIII - 6 Items
360x Pyronic ore

As you can see, If i Really had 16,000cu listed here, finding all the ores would take time.
Instead i am thinking of something like:

Behemoth Heavy Miner - 1 Item
------Equipment
--------Trident Power Cell
-----Cargo 0/140 cu
Behemoth - 1 Item
-----Ores Container
--------360x Pyronic ore
--------140x Denic ore
--------140x Apicene ore
------Weapons Container
--------Axia Accelerated positron
Ragnarok MkIII - 6 Items

And are able to be closed

Behemoth Heavy Miner - 1 Item
Equipment
Trident Power Cell
Cargo 0/140 cu
Behemoth - 1 Item
Ores Container
Weapons Container
Ragnarok MkIII - 6 Items

This way i can quickly find my ore in the ores container

The inventory can already by sorted by type. There is a drop-down list control right above the tree control on the PDA > Inventory > Inventory screen.

+1 to OP, not everything is sorted

I still found it harder to navigate