How are people managing to craft fireworks in minecraft?

you can also load a rocket with stars into a crossbow and it fires it like an explosive, more stars means more damage. one without stars does nothing out of a crossbow, so keep those for the elytra.

paper plus gunpowder. 1 to 3 gunpowder, more gunpowder = flies higher. that alone gives you a rocket for elytra boosting. if you want an actual explosion you make a firework star first (gunpowder + dye) and add it to the recipe.