I have the same issue. It first occurred on my iPad last month Dec 2023. And I was never successful to create a backup after that date. I then I moved to “pro” status and began using my Mac with Sonoma. All files sync without any issues. On my Mac when I try to run backup, it will start and run for about 30 seconds, with apple’s colorful little spinning circle and then stop without creating the backup. Also, the database is located in /Users/MYNAME/Library/Group Containers/9K33E3U3T4.net.shinyfrog.bear/Application Data NOT in root.