Are any differential or transactional records kept in the backups? If some data was written in the middle of the day.. but overwritten at night, I was wondering if there was a way to download the backup, restore it to a local PostgreSQL server, but restore to a particular point in time to get that data that was overwritten. Is there any way to do this? In addition, is there a way to automate multiuple backups per day instead of having to manually do it? Once a day backups done automatically is nice, bnut some apps are critical and need more than that.
No, you have only one automated backup. If you look at the details of your backups you see that those are always roughly on the same time. You could use the API to create more backups. See the documentation here: https://docs.mendix.com/apidocs-mxsdk/apidocs/backups-api/
If you look in the marketplace you can see some modules that use this API but it is quite simpel to build your own.