I have a line art bitmap image from Affinity Photo exported as a svg file. It opens and imports into Inkscape and appears fine in Normal Display Mode but I can’t trace it to convert to a vector format. Once I switch the Display Mode to Outline the image is only a box with an “X” in it. Inkscape responds with “select an image to trace.” Is the screen image of the file the only part that is being exported?
Hard to judge exactly what is going on, without seeing the file and asking quite a few more questions.
However, I’d recommend bringing it over as a PNG, using File > Import. I’d suggest using the “embed” rather than “link” import option. Make sure that you have the image selected, and make sure that it says (in the lower status bar — where it will display the “select an image” text) “image” for object type, rather than something else like “group.” If it says “group”, ungroup it before tracing.