You may want to look at these:
For various iPods:
https://www.youtube.com/watch?v=aybDreAz6Lk
iPod 5th & 6th Gen. NANO section starts around 6 minutes 40 seconds (in this video):
https://www.youtube.com/watch?v=sm7r0pwP8Cw
I'm having no major problems on 10.15.2 Catalina with my hard-disk based 80 GB classic (circa 2008) or 160 GB classic (circa 2013), other than some podcasts (Mad Money) downloaded from Apple show up in both Music and Podcasts, and without artwork (although I've seen that sporadically in the past - may be CNBC's issue). Both have hard disks (micro disks). The 2008 model was rebuilt with a third-party replacement disk and battery about 4 years ago. Minor issues (for me) remain, but not going back to older OS. Plan to buy an iPhone next year or two (and retire iPods when either a next battery or disk goes).
Did find that podcasts added to library are being stored on the cloud, you need to go to the episodes screen and select download to get the podcast on your Mac (so it will sync with iPod). Like the speed control in Podcasts (previously had to play Music or Podcasts in Quick Time to get playback speed control). Like the adjustable time on jump forward and jump backward buttons. Would like to see this in Music application in the future.
Can understand the frustration some are having, as a tester for a company that never upgraded to Win8 or Win8.1 because of a whole slew of problems with critical software that had major issues with Win8 (a real dog) and Win8.1 versions. In my opinion, Windows has been going downhill from WinXP onward. Dumped Windows at home when they stopped supporting Outlook Express, and will never go back.