I would say that it literally does no harm if ancient debris is allowed to be used for decoration on your island. It would incentivise more people to go to the Nether more often. At least make it so that it'll drop the block of ancient debris even if mined without silk touch, yes if netherite was allowed to drop it would break the economy, but surely only the block dropping does no harm right?

 

Could add a crafting recipe for it like every other unobtainable ore.

 

Ancient debris always drops the block, even without silk touch. Netherite scrap is made from smelting ancient debris.

I'm unsure about the economy server, but there are ancient debris on skyblock. When the update was first released, a few people found blocks in bastions before loot was disabled. Needless to say, these blocks are now very valuable and it might be difficult getting support from the people who own them. Having a custom recipe is a great idea, as there really isn't a point to completely removing blocks from a server that advertises as vanilla.

The recipe could be something as simple as putting a netherite scrap in the crafting grid by itself, and getting an ancient debris, similar to how a hopper gives 5 iron. If someone wanted to turn the ancient debris back into scrap, all they would have to do is smelt it.