Correct
The prefix of the snap name shouldn’t matter. Snaps of GTK applications simply declare gtk-common-themes as the default provider, not the only provider. If you can manually connect the theme snap to the application snap, then everything should be ok on the theme snap side.
So the only thing left is to request a global auto-connection for the qogir-theme-snap. This is something that the publisher of the snap needs to do. This is an example of such a request: Auto connections of wine-base-stable, wine-base-devel and wine-base-staging
One more example; this is the request the people from the gtk-common-themes snap made: Auto-connection of gtk3-themes, icon-themes, and sound-themes interfaces