I can't seem to find any QNAP server packages for Minecraft Forge 1.12.2. I'm very inexperienced in this field and would be extremely grateful if anyone would provide a way for me to run a server on my NAS, which runs Linux QNAP. If to help me more information is required, then i'll be more than glad to provide it.
This behavior is the default behavior for items with durability. Actually they disappear when they take damage and are at 0 durability, so you could just deny the usage when the item has 0 remaining durability.
Or you could look at the elytra to see how it swaps out the item for a broken version.