For 1.16.2, along with immune to fire and lava like netherite, I think there should be options that prevent items from being destroyed by explosions or never despawn like nether stars.
Say you don't want your legendary gear to be destroyed when you die and left it there and a creeper creeps up on you and destroys all of your items before you recover them, and you spent hours upon hours just to get your legendary gear. Why should creepers destroy it? Same goes with it never despawning which would be frustrating, but you could still recover that gear?
Immune to explosions would prevent the item from being destroyed by any explosion like nether stars.
Never despawns prevents the item from disappearing after being on the ground for 5 minutes, and it only is gone if it falls in the void, kill command is used on it or a player picks it up.