Since pipewire landed in arch all my issues with sound magically vanished. It's a really great piece of software. Maybe it's even worth to change the distro.

I recommend trying out PulseEffects, my understanding is that EasyEffects is the same project they just did a rename of it. You might be stuck on an older version or something not exactly sure.

Thanks. It's working for me, although I have to leave the GUI window open all the time now.