Echo due to Fx AND the original playback device playing at the same time

Good afternoon,
If you want to get rid of FxSound, try uninstalling the driver manually (since the risks involved in uninstalling the FxSound driver are close to zero).
Please note, you will need to restart your computer afterwards; and you’ll probably still want to check your Control Panel (under “Uninstall or change a program”) to verify if FxSound is uninstalled there, and if not, uninstall it through Control Panel as well.
First, these are the instructions on how to check if the FxSound driver was installed properly:

And these are the instructions on how to manually delete the driver: