When I connect my iPhone to Catalina Beta 4 and select Sync Settings, the Finder opens, and under the General tab, both Backup and Options identify the phone as an iPod. The update works as expected but I'm not sure why the phone is identified as an iPod.
Under the Backups: tab
Back up all of the data on your iPod to this Mac
Under Options:
Show this iPod when on Wi-Fi