I have the same issue. I don't recall seeing it until 1.16.201.02.
We have the same issue - it stated yesterday. It worked fine on Thursday.
Still the same thing, the game will not start. We'll wait for the next release or two to try our luck and I guess then try deleting all our save data sadly.
I run a number of server processes on my server and 2 of my worlds have seen this similar thing. In fact one of them can't even fit inside 16GB of memory. On world was created in 1.16 and the other in 1.14.
They will crash when I attempt to run the world on my laptop with far less memory. One of them is a very small world and the other is about 1GB of save data.