OMG!! OK, I finally think Apple are working on this.
So, I was doing the "smart album" work around all this time, and today I decided I would start over and see if I can get this to work.
disclaimer** I am using developer beta's for both macOS Catalina and iOS. - So, I would assume perhaps in the next public release there might be a change?
macOS 10.15.4 Beta (19E234g)
iOS 13.4
So I did a total restore (wiped) and set the iPhone 11 Pro Max up as a brand new phone.
Installed all my apps, sync'd some music (I don't use Apple Music), and I then tried to sync an album that is WITHIN A FOLDER, not a smart album, but an actual album!.
At first I selected one album, to test, rather than the whole lot.. and I got an error saying that the Photos Library is not ready? or something like that, so I Opened the Photos App, browsed the album I wanted to sync, and then left Photos.app open whilst I sync'd again.
Just as another few points I will mention
- When I re-sync, it still removes the content and then re-adds it all again... not the end of the world, but it would be good if they fixed that as well
- I use two types of 'camera devices' I take pictures with. Apple Devices are .jpg and .heic and are in Albums starting with [iOS] and my Canon RAW (CR2) photos are stored in the [EOS] Albums within the locations of the photos taken (Folder names)
I have a lot more to sync, and will let you all know how it goes. ! can't believe this appears to be working -
*fingers crossed*
In the screenshot below, the FOLDER name is [AU-ACT] Canberra & Jervis Bay and the Albums are below that root folder. It's been a long time since I have seen that !