Videos do not sync from Mac Photos to iPhone
I am trying to sync all my photos and videos on my iMac to my iPhone(s) via iTunes. I have “Include Videos” marked and I have significantly enough space on my iPhone(s). However iTunes refuses to sync any recent videos. Some older videos that had sync‘d previously are on my iphone, but not recent ones. I have updated my ios‘s and have tested this on both my iPhone 7 and iPhone 8. This was a question on another post in 2017 that was not answered satisfactorily. Please advise.
iMac, Mac OS X (10.4.10)