The problem is with the April 2020 "update" MS did to the app.
This thread was started in September 2019, so clearly not.
It seems to have been the September 2019 Windows 10 update that did the damage, and no subsequent update has fixed it.
Some iPhone users seems to have found ways to get around it, but for Android phone and camera users the only workaround seems to be to use File Explorer to manually transfer photos onto your computer. Once there, the Photos app will at least display them.
I am on Android, and the Photos App has worked fine for me all this time - it was only the April update that killed the functionality.
Maybe I was just "lucky" or maybe the longer issue (9/19) is iPhone related?
Either way, MS should just do proper QA before releasing an app with their name on it.