Help With Resource pach for 1.21.11

I am working on a plugin and part of this requires some custom textures for "shards". The shards use the Nether Star as the base item and than have custom textures which should be applied. I cannot get the client to accept the resourcepack, it is ignored. If it is listed in settings > resourcepacks it is red and says it is broken or incompatible. As far as I can tell everything is as it should be, kinda stumped..

If somebody could grab the pack and have a look it would be greatly appreciated, it is here: https://v1rtopia.com/downloads/shards-smp-customs-v3.4.zip

Edit: I just noticed I posted in the wrong section, sorry about that. Could a mod please move it.