In my experience: As far as you can get with any other distro. What do you think Arch requires a terminal for? Genuine question.

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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.

Top left looks best as a default wallpaper in my opinion. Nice mix of colours, not too bright or too dark, and generally seems appealing while not being too distracting.

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.