I don't use EQ, so cannot speak to that.I bought. Did you use the equalizer setting? No matter what I did, I couldn't set it up properly. I use it without equalizer. Frankly, I couldn't hear any difference between the phone's default music app and the UAPP.
The difference between UAPP and LG Music is only on 16/44. LG Music handles HiRes and MQA correctly (bypassing the Android Mixer).
Not everybody can hear the artifacts caused by the mixer. It depends on your music, your IEMs/headphones, and of course your ears. @csglinux posted a clip here at one point to show what it sounds like. Search for posts from him. Also others may chime in with their experiences.