Bastion/Netherite mine portal

Basically, I thought that we could find a very rare structure, it being a nether portal made from crying obsidian that we would not be able to recreate in survival minecraft (so it must be found, not made).

That portal would lead the player to either nether bastion remnants, or a very hidden, almost impossible to find structure in the nether that would look like some kind of netherite mine, and would contain a chest with some rare loot and some netherite, but only 1 chest.

Such portal would make exploration even more worthwhile, as it would give netherite to whoever finds it. Again, the portal should be very rare and found in the overworld (possibly in caves only ?).