Since there is no way to restore app data from google drive's automatic backup outside of first setup (which has come and gone), is there a way to manually access and download the files for manual restoration via root/recovery?
Background: I migrated phones and backed up via adb backup (did not have root). Unfortunately, many apps disable backing up of data through that method. Curiously, some of these apps actually use Android's google drive backup. Most notably whatever version of GMail I had on my phone. After a day of restoring adb backup and setting up my phone, I realized that GMail's and other apps data was not recovered.
Using google drive, I can see that data exists when managing backups and selecting my old phone. How can I download it or access the raw data on my google drive?
The plan would be to use TWRP that I have to put the files in the /data partition.
For the curious, GMail is a pain to configure because I use a large array of filters move mail into various tags, making them act like folders. To see any of that mail, I have to manually click through each tag and synchronize+notify, even though the ones I want to sync are nicely categorized under one encompassing higher priority tag. Of course one day I'm sure they'll make it easier to configure.