Interesting ,so it seems that black pearl gotten betrayed in past and she didn’t always used to be this way but now is cursed to the depth of the ocean.
I have seen some people says it’s salt or pirate is one who betrayed her but I don’t think that’s case,if you remember captain caviar made it very clear that ship is oyster house but different era on top of ship graveyard and if you looks closer at her lobby
I did say it’s possibly ice captain cookie in the past but now I am willing to bet it’s a captain from oyster house and that ship on top of wreckage is theirs.
It seem they and pearl developed a friendship(possibly even more) and they promised to came to back...but never did.
And they made off with her pearl which I am guessing is the black pearl we see in oyster house.(or heart of deep sea but I doubt it) leading black pearl to where she is now...and sad part is small part of her is stilling waiting for them to return