I have a generic Chinese made tablet a Mediatek TYD-108H running Android 6.0 . I have been looking at the automatic backups and something puzzles me. The tablet backs up overnight automatically OK but, when I check the backup it shows only 10 apps have been backed up. Given that I've got about 80 apps installed, I find this puzzling.

1. All apps have been downloaded off Play Store.
2. The backup shows up on Google Drive but with only 10 apps backed up. The apps backed up all seem to be Google apps + YouTube app. Nothing else.
2. I have checked via Settings on my tablet and cannot find any way at all of doing a manual backup !! I have looked in Settings/apps, Settings /Backup, and even looked in Developer options but there is no visible option to do a manual backup.

So, how do I get ALL my apps backed up on the automatic backup and how can I initiate my own manual backup ??

Thanks in advance for any assistance.