Can't transfer Music from iMac to iPhone

Running macOS Ventura 13.6.6 on 2017 iMac

Running iOS17.4.1 on iPhone13

Was able to a couple of months ago.

Is it because the two OS's are no longer compatible? I cant upgrade the software on the iMac, (It's aged out), waiting for the new M4iMac in the fall.

If so, can Apple Music on Ventura 13.6.6 be updated without updating the OS? Can't find an update.

Would appreciate any recommendations and suggestions

Thanks

George