Organising Apple Music Library For Backup

Hi there,

Due to a combo of using iTunes across various platforms for over a decade, not using streaming services, but mainly my bad admin, my Library's in a bit of a mess. I pay for iTunes Match so it's all in the cloud (to an extent) but some music is still on my Mac, and some I've cleared off when I signed up to Match.

What I'm looking to do is download everything to my Mac, create a local backup that I can access, then clear all the local files off once that's done.

I know I can go through, album by album, downloading anything that's not already downloaded, but there's a lot of albums! I know there's an option to show only downloaded items, but is there a way to select the opposite: to show all those NOT downloaded, select them, and set them off downloading?

Cheers!