How can I redownload all my iTunes purchases efficiently?

Re: I gave up on trying to sync the library on my iPhone TO MacBook after deleting MacBook iTunes library. Now I’m trying to load purchases back on MacBook DOWNLOAD ALL does not work. I’ve spent the last two hours and

I’m only to the D’s. Am I missing something ?

Redownload music from the iTunes Store on your Mac - Apple Support

Eg: says:

"Authorise your Mac to play purchases

Before you can redownload music you’ve purchased from the iTunes Store, 

you’ll need to authorise your Mac using your Apple Account."

You may want to check you have plenty of memory / storage space on your Mac:

Eg: A Mac needs at least 50Gb free in which to operate smoothly and do all we ask it to do.

(Music files also take space as well.)

choose Apple menu  > System Settings, click General in the sidebar, then click Storage on the right.

Thank you for your thoughtful reply, and your added info.

I guess you know that iTunes now works from within the Apple Music app.

Re: "There are purchases on my iPhone that are no longer available in iTunes and I want to access them on my MacBook and iPad. I actually re-purchased the ones that were available which is nonsense that I had to pay again just to get them on another device but the ones that are no longer available in iTunes are the ones that really upset me."

Seems Apple doesn't provide a back-up service for purchases.

Apple Support's online articles may help to back-up your purchases for future use.

Eg: Info: About purchasing movies, TV shows, music, books, and ringtones from Apple - Apple Support

Eg: says:

"You can permanently download purchased content to your iPhone, iPad, Mac or Windows PC. Once downloaded, you can access content without an internet connection, and Apple can’t remove it from your device."

________

If needed: To see a chronological list of the apps, songs, movies, TV shows, books, and other items purchased with your Apple Account, view your iTunes Store purchase history.

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Re: "There should be a feature to select sync to iPhone and sync from iPhone.

If you have information on how to sync from iPhone to MacBook I’d be interested in knowing how."

See how to: Access your music library on all your devices - Apple Support

and

How to: Sync content between your Mac and iPhone, iPad, or iPod touch

Other options:

If any of the files you want to share between your iPhone and computer aren’t supported by syncing or transferring with the Finder or iTunes: You can also:

Transfer files between your iPhone and other devices - Apple Support