I think it would be cool if they did a prequel like Descent into Avernus. All we know in cannon is that the duke survives and Elturel returns. It would be fun to play through everything and maybe even meet some of the characters like Zevlor before he abandoned his post. Extra points if they then make a sequel and you can import your characters into a single party. The heroes of Baldur's gate and Elturel joining forces to defeat an even bigger threat.
