What a time to be alive. If you ran into same issue- God bless you and have patience, in my case, issue was inside pubspec file, because I had

module:
  androidX: true

in the end of it, which does not work anymore, it seems. If you ran into same issue, do next:

1. create new project from 0.

2. run it

3. if it runs- copy piece by piece into new project your previous code.

4. project gradle

5. android gradle

6. settings gradle

7. pubspec (few lines at a time)

8. rebuild- rebuild- rebuild.

At some point you will find which code of yours just explodes flutter with no message, took me two days. Good luck.