Interdimensional SU's don't link in different dimensions. They work overworld-to-overworld but neither overworld-to-nether nor overwold-to-end

minecraft 1.16.2, fabric, TR 1.16-3.5.3+build.115

It seems as though the storage is being saved per dimension. Filling up a unit in the overworked leads to an empty unit in the nether, but multiple units in the nether share the storage

Is you chunk loaded in overworld while you are in the nether? What chunkloader do you use?

Yep, spawn chunks and industrial chunkloader in that test world with just TR and Kibe chunkloader on my AoF 3 server.

I have the same issue