Not sure why you put the 6 min limitation of songs, unless it's to exclude almost all but every Bob Dylan song. Having said that, IMHO there is one Pop/Rock song that stands above all other, even 50+ years on. Sympathy For The Devil. Even though the guitar solo is almost all one note, the energy and violence (?) is palpable.
Epic Popular Songs
The Epic Poem stands as the highest literary expression.
To compare lowly rock and pop songs beggars a response.
But so be it. Your nominees have to be at least 6 minutes in length, have a notable instrumental solo, and have lyrics parsing a freshmen college standard. No lists of tress, or multiple battles or dedications to Queens most Glorious.