In macOS, the CD Lookup option is currently a text field. The device is usually /dev/rdisk1.

If that doesn’t work, one way is to simply keep increasing the number (e.g. /dev/rdisk2) until it does work. A less trial and error method is to open “Terminal” and type mount. The output should include a line such as:

/dev/disk2 on /Volumes/Audio CD (local, nodev, nosuid, read-only)

You need to replace /dev/disk with /dev/rdisk, so if, for example, it says /dev/disk2, you should enter /dev/rdisk2 in Picard’s preferences.