Launch options need to be set in their own "Arguments" line, it should work then. Like this:
And if you also want to use the "GDK_SCALE=2" environment variable, as suggested elsewhere in this thread, this would need to be set in the "Environment Variables" line.
Perhaps Equalizer APO might be what you're looking for. Served me well when I still used Windows. IIRC it's a bit more advanced, so not as "easy" as EasyEffects, but a great tool nonetheless.