For my LineageOS phone I use ADB: adb pull /sdcard/DCIM/Camera
to get photos I’ve taken for example.
OP may need to install ADB and enable USB debugging. Here’s a guide if they don’t know how
If OP installed GrapheneOS they likely already have adb and USB debugging configured.
That said, as recommended in the FAQ, one should use android-file-transfer, since enabling USB debugging (and using adb) is a security breach
Actually, I always end up using ADB tools to get files or photos, you can get recursive files to get them all. I do it even with people that tries to get photos from their Windows machines, so I don’t think it’s a problem with Linux neither. This is the best way to get safely and correctly all your files.