Well i'm clearly not going to change your mind with facts, but Dave's HP out has
1% distortion (so clearly not zero) vs 0.0004% on the Oor. As for the Hypsos, i liked it in combination with the Oor and wouldn't have bought the amp without it. Or without the xlr and power cables i used to test.
I get it,
you like direct Dave. I do too. I just find it lacking in several areas compared to any decent headphone amp. Tested the Burson 3x GT as well. That had much poorer blacks than the OOR + Hypsos but still better than non filtered Dave. The filter/generator help You can put as many horses as you want in front of a carriage, you still won't make it a car.
I've tested everything myself and I have no interest in the current flavor of the month. I know people enjoy messing around and any changes they can call improvements, but I've wasted enough time chasing the latest " Pro tips ".
You need to accept that just because you like something, doesn't make it the absolute truth. Just like you say the Susvara/ Stealth are driven great by Dave and everyone disagrees. I was tentatively inclined to believe you before listening to them myself. Susvara sounded literally broken from Dave, and almost as bad with the OOR in SE. It was with 4x the power in balanced mode that they actually started to sound good. And I hated Susvara out of TT2 as well when i first listened to them.
It has nothing to do with clipping or etc. There is just considerably better soundstage, 3d imaging, separation and dynamics from a better amp.
If keeping the Dave on will overcome that, I'll gladly return the OOR
but i doubt it. Listening now after keeping it on for 24 hours, I don't detect any difference.