I made the portal in the ancient city, at coordinates 181 -49 -720, then I enter the nether, after that, I break 1 obsidian block, changed the portal from 2x3 to 3x3, like what I followed from the YT Video, then went back and it teleported me to the cave (also tried again, then to the deep dark cave).

I don't think I threw items after I changed the portal to 3x3, try it, it may create a new portal and not link to the ancient city.

It looks better if they made built another new portal without destroying the nether portal, it should create another portal. I didn't want to farm obsidians with nether portals because it's just wasting time.

Seed: 6580498518238753

I follow the tutorial from this one: https://www.youtube.com/watch?v=Nmtbcw7miLg&t=553s

I wasted more than 2 hours on this trying to link the nether portal correctly, it didn't make it until I got all of these, and it worked, I had to follow the tutorial very carefully. It was painful wasting more than 2 hours, I don't want to get too bored with that game.