No luck in the Owner Profile unfortunately.
At least I know that it should be supported so I can keep testing things.
Perhaps I changed a setting early on that is stripping all this metadata, not sure.
I was able to get that 'no location' popup you mentioned by doing things really quickly, but even when the popup doesn't appear there's no location data.
Just checking that when you say Gallery app your mean the default Gallery app in GrapheneOS?
The fields I see in Photo details are - Title, Time, Width, Height, Orientation, File size, Path
When I use the Google Camera I get more fields, but no location.