If you upload it and make it public, you will very quickly get kicked out of the instance as soon as someone reports your library as containing copyrighted mate

If you upload it and make it public, you will very quickly get kicked out of the instance as soon as someone reports your library as containing copyrighted material. If may try to be coy about it and abuse the "invite-only" mechanism to share with lots of people, but you are still risking getting reported. There are also moderation tools in place that can let the instance admin see beyond the "privacy sharing" settings, so a more zealous admin would be the first to want abusers out of their servers.