Mac iTunes iCloud Status "Waiting" & disabled, but…it's mine?

On this Apple Support article:

About iCloud Music Library icons and status - Apple Support

…I posted this (because it's unhelpful in this situation):

"iMac (Retina 5K, 27-inch, Late 2015)

macOS: 10.13.5 (17F77)

iTunes: 12.7.5.9

Regarding this article:

iCloud Status "Waiting" does not show any icon, at least for the one song in my library showing that.

iMac not disconnected from iCloud Music Library.

This is a 350MB song mix (not expected to upload).

Was working on iPhone and iMac, but after sync is removed from iPhone and now it's grayed out on iMac and I can no longer play it.

Cannot Show In Finder, and iTunes reports Location is iCloud (how did it ever get there?).

BUT it's MY mix so is not in Apple Music, not in a different country or region.

Restrictions not enabled.

1. Please add "Waiting" to the list of criteria under iCloud Status in Smart Playlists for debugging song files (not currently an option), and…

2. Seems like there should be another status for this odd situation. Or just fix the glitch (if there is one) for this sort of song file."

The most recent Community post on this was a year ago:

Problem with iTunes/iCloud "waiting" status

…but it's too old, so Apple closed if for replies.

Per Apple's instructions, I'm asking again.

First, how can I restore a song from iCloud Music Library to my Mac, that should never have been uploaded in the first place because it was too big, and has apparently been stripped from my local iTunes Library without my permission?

Second, how can I prevent this nonsense in the future so my own live mixes don't vanish?

Finally, I have BeaTunes but it's clunky, and I haven't found anything else as good or better than iTunes for Mac. Is there a better Mac music library manager than iTunes?