I looked, whilst photos appears as a folder in drive, there is no option to "download all", and it would require me to load them into the browser view, select them, and then choose to download them.
For reference, I have 125GB of photos since 1994 in there... it would take a very long time to select them all.
You can install Google Drive Desktop and sync them to your computer all at once.
Could you use the Google Drive program and then sync that folder to your local machine?