Doesn’t matter if the pinna is bypassed or not. 3d audio (soundstage) requires both ears to receive signal from the same point source. The time delay between the two ears receiving the signal is the crux of the entire premise. Headphones inherently defeat that entirely by having the entire ear subjected to one side of the audio.

Ergo, headphones do not provide any 3d audio or soundstage.

Headphones do not provide soundstage.

https://headphones.com/blogs/features/soundstage-is-much-more-complicated-than-you-think

Not to argue in favor of eating dogs or anything, but I think posting a source would really help the claim you’re making.