I have a MacOs, recently upgraded to ventura - though in Monterrey happened exactly the same issue.
As I the latest .dmg for the MGPicker , the installation start to happen at a certain point I got a fatal error.
Also, in case it helps, I can´t upload images to this thread to complete . A buggy system is not recognizing the image I´m trying to upload - it´s just a regular low size screen capt.