It’s not just the Galaxy A51 and M30s, the Galaxy A71 5G is also receiving One UI 3.0 update with Android 11. This software, A716USQU2CUA7, also includes the January 2021 security patch.
Again, this is for the 5G version of the A71 (SM-A716U). The 4G version of the phone (SM-A715) will have to wait a while longer (the original schedule had the A71 phones getting the update in May).
Android 11 and One UI 3.0 arrive on the Galaxy A71 5G
You can read our One UI 3.0 mini review (or watch the video) for a look at the visual changes and new features.