If your Android phone is running out of storage space, many phones will allow you to insert an SD card, which you can set as the phone's primary storage.

and you can drag and drop files to the phone’s internal storage or the microSD card by tapping on the storage option at the top of the Android File Transfer window. It’s slightly easier to transfer ...

In a nutshell, when Android 6.0 sees that you’ve inserted a microSD card the operating system will ask if you’d like to treat it as portable storage or as internal storage.

I see a combined 192 GB in the storage analyzer in Settings, but it's split into 64GB internal and 128GB SD card. I can't seem to create any folders in the Google Files app.

If your ROG Ally is running out of storage, you can move and install games on an SD card.