It could be due to an uncompleted quest prerequisite. Maybe there are certain side quests on the Nameless Isle that need to be finished before the Red Prince's story can progress. Check if there are any quests related to his backstory or the local lore that are still ongoing.
Reload a previous save. Sometimes, during gameplay, something might have gone wrong that prevents story progression. By reloading an earlier save, you can try again and hopefully avoid whatever issue caused the block. Also, make sure you've explored the entire Nameless Isle. There could be a trigger or an item in a hidden area that is necessary for the story to move forward. Search every nook and cranny, interact with all possible objects and talk to every character you come across.
It could be a glitch in the game. Try restarting the game or reinstalling it to see if that fixes the issue. Also, make sure your game is updated to the latest version.
Maybe it lacks certain key elements or plot devices. It could be that the character is not developed enough to drive the story forward, or there are external constraints in the narrative structure preventing its progress.
It could be that you're missing an important item or haven't interacted with a key character. Sometimes, it's a matter of exploring all areas thoroughly. Also, make sure you haven't overlooked any instructions or dialogues.
In Red Dead Online's advance story, leveling up your character is crucial. As you gain levels, you'll unlock new storylines. You can level up by doing various activities like hunting, fishing, and participating in PvP events. Another way is to follow the leads given by non - player characters (NPCs). They might point you towards new parts of the advance story. Don't forget to upgrade your gear too, as better equipment can make some of the more difficult story missions easier.
Maybe it has some bugs or glitches that prevent the story from progressing. It could also be due to incomplete coding in certain parts related to story advancement.
Perhaps you haven't completed all the side objectives or requirements for a particular main story mission. Go back and review the mission details carefully. It's also possible that there's a conflict with a mod if you're using any. Try disabling them to see if the story can then progress.