Where can we submit the feedback? The general Cover email?
From most glaring to least for me:
I am sorry if this is "can't unsee" material, but her eyes (especially the iris) look concave. The iris resolution between the top shaded part and the bottom bright part is different, with the top part being visibly blurrier. Add the horizontal shading & her iris highlights located right at the border between the shading changes and that makes iris look very wrong. This is most obvious when the eyes are fully open and she's looking to the side.
Saturation. I usually left my wide gamut monitor alone unless I need the color accuracy, but I have to clamp it to sRGB for her (and Bae). Especially the hair, but the whole model look a bit too vivid in general.
Mouth tracking during singing can be better. Tracking during speaking is fine tho.
Smaller gangimari iris & more obvious blush expression.
Breast jiggle is a bit much, almost DoA level. If IRyS have to cover it with tofu every zatsudan stream it, I think we are better off with reduced jiggle for general stream (give it toggle to unleash the full jiggle during members' only stream?).