Is Ubuntu MATE compatible with Google Photos or is uselless to keep trying?
I'm not aware of any official desktop application for Linux to sync Google Photos, but it is always accessible from the web at https://photos.google.com
If you're looking for a way to sync the files themselves between Google Photos and your computer, try a Google Drive client like Insync (paid, has free trial) or google-drive-ocamlfuse (free, open source).
Be sure to enable something in Google Drive so you can see Google Photos:
Organize photos & videos using Google Drive
You can move photos and videos into a folder, but the folders won’t become albums in Google Photos.
- On your computer, open drive.google.com.
- Click Settings > Settings.
- Check Create a Google Photos folder.
- Click Done.