My understanding is that the mote nexus, when broken, will drop any and all contained contents on the ground. This feature is sensible for many storage blocks, but not something like the mote nexus, and it very much should be changed.

The mote nexus is explicitly advertised as able to hold 1023 types of a 'arbitrarily large' number of items. Even if it was limited to 1023 ordinary vanilla stacks, this would be dangerous behavior - equivalent to breaking 38 chests all at once. But with no cap to 'stack' size, breaking a mote nexus could produce thousands, millions, or billions of item stack entities. Similar item storage solutions like AE2 or Drawers will almost never individually drop the contents of storage when broken, for just this reason.

This would instantly crash the server. Generally, having blocks that instantly crash the server if a creeper explodes on it is not a good idea. I would strongly recommend this behavior be changed.

Make it keep items when picked up, or make it void all items when broken, or make it drop each mote as a single vanilla stack with more than 64 items (also a indirect way to get larger than normal phials), or make it drop a 'nexus remnant' that will transfer the contents to a empty nexus when used on it, or make it convert all contents to media, or make it teleport away like a dragon egg.

Anything but crashing the server outright.