2FA unavailable, neither root nor admin let me in. And now?

[NotOrAnd]

I have lost my phone with my 2FA token for my AS4004T (vADM Version: 4.0.5.RRS1)
I can still access the device via SSH and can successfully escalate privileges with sudo while neither root nor admin let me in.
How do I reset that 2FA token?
I need to keep all configurations and disk contents, of course.

On the NAS itself I have also found the tool "/volume0/usr/builtin/bin/google-authenticator" and run it.
It gave me a URL to re-create my token with my phone, but it didn't work: it keeps saying my password is wrong, despite I have successfully set it up via command line (with "sudo passwd admin").