VERY slow sync (hours!) for pictures via iTunes for Mac since last Mojave and iOS updates (3/2019)

Since I updated to the latest Mojave 10.14.4 and the latest iOS 12.2 this week, synching my photos to my iPads and iPhone is abysmally slow. Granted that I have over 25,000 photos but up until this week (and these updates), if I add a few photos to one folder (10-20 or so) then they'd synch in a couple of minutes. Now it takes several hours, just for a few new photos. I have already rebooted my (27" 5K Retina) iMac and my iPads, and I deleted the iPod Photo Cache to start from scratch. I thought once I got the Photo Cache reestablished, that the sync would be fast again like it was before the updates, but that is not the case. I am using a USB cable plugged directly into my iMac. Does anyone else experience this and does anyone have any other suggestions? Is this enough info to help me? Thank you.