Fair play mate, if you still feel the same after then it is what it is; I will trust you to convey your honest experience. A lot of people complain about the pads/comfort because the opening is small AF. I have small ears so it's no bother for me. Cups don't even touch my lobes once settled in. But I don't only recc the pads for comfort, the sound changed for the better on mine - but other users swear by the original pads so not sure what's going on there. In any case, as you've already tried that setup, you know your head/ears better than anyone.
Just ran On A Level through my ifi iDSD Micro BL and it's definitely at basshead levels with no distortion. Volume is just past 12 O'clock on Normal power gain - all switches off. Could go further, but don't really feel a need to. With the EQ curve shown, the highs are definitely muted, but it's very fun! This was my first attempt with APO, I'll get used to it eventually; much more used to the simplicity of the Creative E5, but I recognise the potential if I can tap into it lol.