I feel like something like this came up in the upstream bugtracker, but can't get a hold of it. Can you try if this is still a problem with the 5.6.0 appimage: https://www.digikam.org/download/
- Bug#869148: Acknowledgement (digikam cannot import... Simon Frei
- Bug#869148: Acknowledgement (digikam cannot i... Herminio Hernandez, Jr.
- Bug#869148: Acknowledgement (digikam cann... Simon Frei

