Career is on the 2023 roadmap and they keep reiterating that this is still going to happen.
Assuming carreer comes (I think Oct/Nov) that also will mean that create a boxer will be available at the same time.
From there They would only finish adding venues and features to EXISTING Modes. Maybe Career starts simple and q1 2024 gets managers/cutmen etc ...i don't really know. But There isn't much more to add other than venues and fighters - and those can be added even after a full release as there is already quite a lot of boxers and a surprising number of venues (way more than they need imo).
So my guess is Holiday season (Fall Winter) of next year 2024. The Caveat there is - console optimization and bug/beta testing idk how long that takes - but I really don't think they want to drag it out very long. They will need that $ to start looking towards the future.