So it seems like SBM3 server side copy doesn’t work with GVFS.
I found there is a feature request for it: GNOME/gvfs#286
Its about 8 years old.
It seems like all the parts are available just… not connected?
Is there someone we can bribe to get this working?
Refer comment https://gitlab.gnome.org/GNOME/gvfs/-/issues/286#note_998110.