Realism again? Whatever that means? Google mastering studios and look at their equipment lists. You'll find very few that look like anybody's high-end audiophile system. Find the few that do. Narrow it to the systems, if any, that use the speakers you own. Tweak your room like...well, let's hope there isn't more than one of them. Now, buy recordings mastered in that room, you've got something approaching relative "realism."
For everything else, it's seeking accuracy and accepting systemic strengths and weaknesses. The strengths of a really good headphone system are good ones -- elimination of room resonances and ambient noise. You can struggle for years, spending thousands of dollars to minimize that stuff. Pop on a good pair of cans and it's gone, resulting in a resolution of detail and an isolation from distraction that cannot be achieved with speakers outside of a darkened anechoic chamber with a silenced HVAC system.
I go'cher immersive right there.
The weaknesses? Imaging and slam. At the quiet end, dynamics don't get any better, because a quiet, isolated background doesn't get any better. At the other end, headphones obviously can't deliver the chest-thump that big bass drivers moving air can. And the imaging is, well, very different. You can either get used to it or not. The soundstage, what headphone geeks call headstage can, on the other hand, be huge. The room becomes a moot point. It is no longer a limitation. You're pumping the recording right to the eardrums so the only spacial limitation, other than the inability to lay instruments out in a horizontal plane in front of you - pinpoint imaging - is the recording. It can be a stunning illusion. I got'cher wall-disolving expansive soundstage right there, too. And I can get it ina closet if I need to.
Headphone listening can be a revelation, but before you can appreciate it, you've got to accept that what were seeking is varieties of an illusion. Then you can accept the strengths and weaknesses of the various illusions for what they are, and enjoy them without chasing some "realism" that only existed in the mastering suite. Seek accuracy, if that's your thing, tone if that's your thing. But spatial realism? You can only imagine it.
Tim