How does one restore data to phone from Google drive? I backup my data from my Android phone to Google Drive. I then performed a full factory reset. I was given the option to exchange data with another phone, but not restore from Google Drive.

When I go to Google Drive from the app, I'm able to see the backup. I can view the files, but the only option I'm given is to delete them.

Is there something I'm missing? Why can't you restore incrementally from Google Drive? And how do I get my data back without having to do another factory restore? Finally, why wasn't I given that option when I perform the factory restore?
Here's a real-life case on someone who'd gotten Google Backup to restore indirectly without root: screenshot

As I recall, a manual trigger for the G Backup restore function was planned for the Pixel series, but this was over a year ago that I'd read about that so I'm not sure what became of that; at that time, an ADB command existed to trigger such behavior, but I'm unsure what the prerequisites and/or limitations are.

My post here also briefly touches on G Backup and other methods I'd explored to solve my own issue with restoring a backup file's data.  Note that there is versioning requirement for the standard restoration method(s) to work, i.e., you can only restore onto a device running the same or higher  of Android (if even then).

Finally, here is a guide I wrote (and fixes) for an Android game, but the same functionality can be applied to more general usages as well.