In Outer Banks season 5, Chandler Groff plans to sell the Blue Crown to a buyer in Portugal. This detail appears in the season’s opening storyline, as the Pogues try to recover the artifact after JJ’s death.
The Blue Crown is the treasure introduced through the Blackbeard mythology developed in seasons 4 and 5. Groff’s plan makes Portugal an important destination in the early episodes and gives the Pogues a reason to leave Morocco while pursuing both the artifact and revenge.
Portugal is not the country where the Pogues find JJ after the season 4 finale. They arrive in Morocco before the events of season 5, and the crown’s planned sale creates the next international stage of their adventure. Croatia, meanwhile, was used for filming, not as Groff’s intended sales destination.