Admin account locked out with TOTP! QR Code is not accepted

Real bullshit happened to me.
I had to set up TOTP again because of a smartphone change. Please don’t ask why I didn’t just restore the backup to the new phone…I thought this would be faster.
Long story short, due to a mishap TOTP is not set up on the smartphone for the admin, but am no longer logged in on the computer!
Now comes the following screen when logging in:
2021-11-03 18_26_18-Window
When I try to scan the QR code with the TOTP app, nothing happens. No error message, but the QR code is apparently not accepted. It looks very strange to me anyway.
What else can I do but bite the edge of the table?

Problem has been solved. I was able to help myself.
The following forum post (last entry) by @Davoud was helpful:

You encountered a bug: Invalid QR code during first login of a user · Issue #1147 · nextcloud/twofactor_totp · GitHub