So while yes, for some people in certain regions updates will roll out according to the roadmap, in certain regions, users will have to wait a while. For example, the Galaxy Z Flip 3 has received Android 12 in certain regions already in accordance with the roadmap, however my unit here in Kenya is yet to receive the update.
If you’re in these countries, you can go to settings > software updates to check manually for the update.
For these users, the update is rolling out just a few days before January when it should have rolled out according to the roadmap. Hopefully for other users across the world, Samsung sticks to issuing the update on time.
I am still hoping the Galaxy Z Flip 3 receives the One UI 4 update before the end of December 2022. It is 3 days to go.