I wanted to test the snapshot 20w51a today. (for 1.17 Caves and Cliffs Update for Java Edition) I've seen it in several YouTube videos that people have played it. Now I wanted to test it too, but the version is not displayed for me. Only 1.16.5 is displayed, which is already playable as a full version.
My launcher has all the updates. Is this version publicly playable yet? Am on MacOS BigSur, MacBook Pro.
At the top left you can turn on developer versions - you have to check it
I already have the solution, you are not allowed to use the latest developer version at the moment, because it is viewed as 1.16.5 for whatever reason. Create your own installation and manually select the snapshot. At first I was just confused because the wrong version is displayed.