Elytra engine

This would be an elytra "attachment" that could be crafted. It would be some kind of engine or something, and would power the elytra, giving an alternative to fireworks. When attached to the elytra (perhaps with a smithing table or anvil), it would allow the user to fill said engine with coal or some other kind of fuel, which would then give thrust. Obviously we don't want to outright replace fireworks, so it should definitely be slower than the thrust that fireworks give off. It should also be pretty hard to craft, maybe using netherite, a nether star, a dragon egg, etc (or maybe a brand new item?) As an alternative to crafting, said engine could potentially be found in a new structure or dropped by a new boss? But that would also require a new structure or boss, so maybe not. Another cool potential addition could be that based on what fuel/item you put into the elytra engine, it has a special effect, such as gunpowder giving a speed boost at the cost of durability, or a lava bucket giving off a trail of fire particles that light mobs on fire. As one final note, maybe this could be tied in with new enchantments? (For example, an enchant that makes the elytra engine require less fuel)