OMG! Ubuntu! published a tutorial about how to fix GNOME Sushi in Ubuntu 20.10.

GNOME Sushi Doesn't Work in Ubuntu 20.10, But There is a Fix

GNOME Sushi doesn't work on Ubuntu 20.10, failing to preview anything. A workaround is available for those willing to put in the effort to get it working.

GNOME Sushi Doesn't Work in Ubuntu 20.10, But There is a Fix - OMG! Ubuntu!