It has been long reported that Microsoft is looking to do an overhaul to its Achievement system that would potentially include a Platinum-type award for fully completing a list of Achievements. According to Insider, Shpeshal Nick he states that Microsoft is nearly done with the changes happening to the system.
“Xbox are nearly done with their Achievement overhaul with changes to Achievements, and we should see it next year (2024).”
He also talks about how it could be one of those things where it has to go through multiple rounds of Beta testing so that’s why we aren’t sure exactly when it will come out yet.
(Rumor) Shpeshal Nick has heard that Xbox is nearly done with their "Achievement Overhaul" and we should be seeing it sometime in 2024
— Idle Sloth💙💛 (@IdleSloth84_) December 31, 2023
This comes from the Xbox Era Podcast which you can watch and listen to on YouTube.