It is my humble advice to m51 users to not update to android 12 (whenever it comes) until the bugs are detected. One ui 3 is running smoothly right now on M51. Don't ruin your phone for just to upgrade.
Even they are taking so much time to deliver the update for Galaxy M51, we are assuming that they will give the update with less bugs as they are taking time but this not true because they took time even for A71 and still there are 2-3 major bugs.I h...
S20 Fe 5g already got the 5g update with one ui 5.0, may be the 5g services in your area is not active yet. Check with ookhla speed test for 5g coverage in your area