music transfer Mac air to iPhone no iTunes

Here are the Finder instructions→Use the Finder to sync your iPhone, iPad, or iPod with your computer - Apple Support

(I didn’t post it initially because the link was broken; it seems to be fixed now).

MacBooks come with iTunes preinstalled. Did you remove it? Except with MacOS 12 (Monterey) it is called “Music” rather than iTunes. And also with Monterey you don’t use iTunes/Music to transfer music (and other) content to your iPhone, you use Finder.

If you have Apple Music or iTunes Match all of your non-Apple music is already accessible on your phone through Apple Music library. If you open the Music app on your phone you should see it.