If you are an active Game Pass Ultimate subscriber, starting tomorrow (6th July, 2023), you'll be able to get your hands on the Obsidian Banjo Pack as a perk for a limited time.
Source: Xbox Wire
Sea of Thieves: Obsidian Banjo Pack – July 6
For a limited time, claim items from the prized Obsidian set! This pack contains the Obsidian Banjo, Onyx Compass, and Obsidian Hull. Perk content requires Sea of Thieves to use.
As someone who got the Banjo originally from the longsleeve t-shirt purchase, I'm glad to see it finally make its return! It's long overdue. Hopefully, it will put a dent in the scalpers trying to take advantage of its rarity.
Note: if you usually play on Steam, you will need to load up the Microsoft Store version to have the pack applied to your account. However, Game Pass Ultimate also allows you to stream games from XCloud (controller required on PC) and that will work also. Just load into the game for a couple of minutes, and you should be set.
Update: Now live! You have until the 5th of August to claim the code and you must redeem the code by the 12th of August.