It does not support direct sync. However,
prod's MCiS still works fine as long as you don't upgrade iTunes past version 12.5.5.5 (ish, that's what I'm using, and you can still find installers for that version around the web). That version
does support iCloud Music Library and iTunes Match, so if you have that, it is absolutely possible to sync your MC Library, or a subset thereof, to your iCloud Music Library and then be able to access all of it (and smartlists generated by MC) in Music.app on your phone.
You can script it, with some elbow grease, to happen automatically. It isn't perfect, but it works quite well.
That's exactly what I do.
One of these days I might update the source on MCiS to work with newer versions of iTunes (I'm sure it is a minor API change-induced bug), but the existing version works for me so laziness has won thus far.