Yeah, just throw more bandaid fix feedback at it. (just like the zero auto former you push for the OTL’s into hard loads)
Everyone know too much feedback is detrimental to the sound, that’s why that GaN by GaN Class-D measured by Amirm had "very little feedback on it" programed from the owner, for the sake good sound, but of not measuring too well in certain parameters. (get with the program) and you and your mate stop putting on everything that’s in opposition to what you’ve got coming, not just on this thread I’ve seen but others too!
And btw you can’t cure this kind of -75 degrees! of phase shift (red) with loads of feedback https://ibb.co/S06J7hf only a 4 x higher switching frequency will move that up out of the audio band!!!