Can't sync iPod nano with music?

I have an iPod nano (gen 7, that was a free Apple replacement for my classic nano). My iMac has updated to OS Catalina and now I can't sync my iPod with my music library to update my playlist. Searching Apple support seems to suggest I have to subscribe to Apple music or iCloud music to access my own music library from all my devices. Is this correct?

Would this explain why I also can't access our library from other iMacs in the house despite them all being logged ob to same Apple account?

Have to say I am getting fed up of Apple updates that suddenly make your perfectly good devices useless! If the above is true we will find ourselves with 3 iPods that we can no longer use!