Time Machine - no disks appear

I wanted to get rid of old backups and erased the external USB drive partition that I had been using for Time Machine backups. After that, I wanted to set up Time Machine again but in the Select Backup Disk menu I accidentally removed the old backup disk but now no disks appear in this menu, even after waiting for a longer time.

The external USB drive works well and the respective drive is visible and accessible in Finder.

Using MacbookAir MacOS Big Sur 11.6.

Thanks in advance for your help!