Catalina: Photo sync does not work properly (Finder/USB). NOT using Photos app. NOT using iCloud for photos.

This is my first thread on the subject - which I accentally marked "SOLVED"

https://discussions.apple.com/thread/250716061

I have been following my thread and another one (which uses the Photos app) for months. The only way that works for me to sync photos is to turn on iCloud photo sync on the device (let's say iPad) I want to sync, then let all the photos on the iPad delete, then delete the iPod photo cache on my iMac, then start the sync from scratch. Today it took over 2 hours (fully updated iMac and iPad Pro). I've been waiting since before Catalina (see my OTHER thread here):

https://discussions.apple.com/thread/250270137

which I was only able to "fix" by rolling back to a previous edition of iTunes - for these issues to be resolved. So, this has been a problem for me for several months. Anyway, today I tried with a second iPad (turning on iCloud photos on the iPad, waiting for the photos to disappear, then connecting via USB to my iMac) and the arrows just spun in Finder with no photos being synched (no pie chart ever appeared). I did not delete the iPod Photo Cache this time, hoping I wouldn't need to.

I don't think that we should have to follow all of those steps and wait for hours (I have over 30k photos) every time I want to sync photos from my iMac to my iPad or iPhone. For years, the process was smooth and quick.

I do not use iCloud or the Photos app. The people on a similar thread who use the Photos app think the issue is with the app. It could be, but I believe it goes deeper as I've never used the app and many other people commented on my thread who also do not use the app. Apple has never responded to me though I have complained through the various contact links many times and event talked to phone support. 

I'm starting a new thread as my first one was erroneously marked "solved" and I'll be careful not to do that again this time, until it is SOLVED. Thanks for reading.

Any other workarounds besides what I have mentioned above are welcome.