I seem to have solved it! Went to Settings --> Apps --> Edge (modify) Then did a complete reinstall of Edge completely. It loaded cleanly and identified what was probably the source of the malware, an add-on.
The people at the Windows help section made me go back again to the removal guide, and I thought "what the hell" I'd look through my list of programs one more time. Again, there wasn't any program to uninstall. No obvious malware. Just reinstalling Edge worked, and I seem to have cleared it up!