How to limit Google account access to selected apps?
There are two ways to do it.
Method 1 - Ugly
If your phone supports multiple sessions (I mean this), then disable GApps except Google Photos in the new user session.
Method 2 - Better
Use Parallel Space and just run the Google Photos A.P.K. in it
I'm not sure here but I think if you are a privileged user you can direct the sign in to a webview.
As suggested by @chx, Shelter is good, I just tested it, makes clone for these apps when I tried to do it for Google Photos.