I don’t use crossfeed except for sometimes with old stereo recordings that are super hard panned left and right. And for those I’ll use Waves Nx just so my brain isn’t trying to make sense of one instrument being only in the left ear and a different instrument being only in the right ear. I’ll also use Waves Nx when I want to listen to a surround sound mix on headphones. Cause Waves Nx is the best way to listen to surround sound on headphones other than buying a Smyth Realizer.
The good amps and headphones now have gotten much better at presenting a coherent and focused center image than the headphone gear of old. The headphone gear of old would do a blob around each ear with no connection in the center. And you needed crossfeed to fix that. The right style of modern headphone gear is now able to do a focused and coherent center image that can even be out in front of your forehead. And with good gear like that there is no need for crossfeed, except for maybe some of those old stereo recordings that are super hard panned left and right.
Yellow submarine and lady Madonna by Beatles was recorded on an old 8 track so some monophonic speakers you only heard half the song. Charlie Puth talked about this and in his song Left and Right takes the concept to an extreme. He talks about it with Jimmy Fallon. I found it really interesting.