Trying to change my root password I followed a hint that I just had to type sudo init1 and then passwd and I would be able to change the root password.
But that was not right.
After typing sudo init 1 and enter, the connection was cancelled and I was not able to rebuild it. The pi ran headless.
Now I connected a monitor and a keyboard. The Raspberry starts until the "Welcome to PIXEL" screen.
That's it. No more action.
Is there a possibility to undo whatever I changed?