I've found a possible solution for if you have unwated photos in your Lightroom Sync que.
The problem is all the instructions are saying you need to delete from the ONLINE "all synced photos" album. This is incorrect.
Where you need to delete the images from is within the lightroom classic catalog on the desktopthere is a sync folder with every image that is online.. or is waiting to be uploaded to the cloud.
With Sync paused, once you delete from this location, it stops the upload of unwanted images.
And then once you resume upload, it takes the unwanted files out of the que.
I'm using LIGHTROOM CLASSIC 2021
Pause sync in Lr Classic
**CORRECTED STEP** go to to side panel within DESKTOP version of lightroom classic, under catalog select ALL SYNCED PHOTOGRAPHS,
Tidy up the collection e.g. delete jpegs, only upload 5 star images, only upload edited images, ect.
Mark the collection again for sync and activate sync again – deactivate pause (click the cloud, and start sync)
Hope this helps!
**P.S. for issues with chronology and sorting images, use your Library Filter. You can get as detailed as you need to be able to sort the images, usually this is set to NONE. All you need is to pick a different option like Attribute or Metadata (this is located above the images)