How to get a force a fresh total re-sync of my local music tracks on to Apple iTunes Match/Cloud, when they show Removed in Cloud status?

Catalina 10.15.7, new iMac

I uploaded and matched 15,000 tracks on my iMac via iTunes Match to Apple's cloud (after stopping my subscription to the larger service Apple Music Cloud).

Then I found that many of the tracks were not actually playable on my other devices, although they were appearing in the respective Music apps fine.

I also found some instances of corrupted metadata of at least one album.

Logging off and stopping Sync, deleting and reimporting some of the tracks and respective albums in Music on my iMac, did not solve the problem.

So I then created a new blank Music library and synched it to my cloud. Once all the tracks were there, I proceeded to delete them 900 by 900 at a time, and let the sync on for a few hours.

That deleted all my music in the cloud apparently since none of it was showing on my devices.

Then (after logging off and off the Sync) I proceeded to switch back to my proper Music library and my 15,000 tracks. Once I re-logged and enabled sync, I was expecting a new fresh upload of all my tracks.

Instead I no upload took place, and all my tracks were tagged Removed (Cloud Status).

Tracks and Music library are fine, they still play on iMac of course. However to enable each track to sync to the cloud it appears that the prompt only works one track at a time !!! No batch option it seems.

So somehow there is a cache or info on my iMac that remembers which tracks have been matched or uploaded before, or Apple's cloud still has a memory of which tracks were there.

How to resolve the sync via iTunes Match efficiently (ie not one track at a time)?