Malevolint
500+ Head-Fier
You've got mseb and the ability to use different apps as music players. That plus the power and more slightly neutral and more resolving signature puts this thing in the top of the class at this price point imo.
Oh, and it's dead silent with all the iems I've tried, even the 64 audio tia forte. The other daps I've tried before hissed a bit, even with my akt8ieii. That includes the sr15, m11, and zx300/wm1a. Now that wasn't a lot of hiss on those daps, but I could hear it. It wasn't enough to bug me during regular listening, but the r5 is very quiet.
I agree! Sounds like they are old school and want something with only music, no apps. I don't think you can do better than the zx300 at the price point.