I'm not quite sure of the "burch theory" but I can say that the Gospels, which you advocate and deny esoteric exegesis are in fact the creations of an esoteric comprehension which has gradually been lost in the materialistic milieu.
This is aphoristic but as example the Mark Gospel , which was written after Golgotha is seen as the work of the "Lion Lodge" to use a term of modern times, that esoteric or occult comprehension noted in the Apocalypse of John within the Eagle, Lion, Bull and Man.
The four pictures can be appreciated as ancient mystery centers seeing Man as the expression of one, or in this case 4 different types , all in an evolutionary sense. When the ancients looked up to the stars and while seeing Man as the expression of the divine we see these four beings (spiritual )working through man, in time and place.
The Matthew gospel( Man as he progresses), the Mark Gospel ( the Lion which can be related to the juror), the Luke Gospel ( the Bull and related to divine healing- of course Luke was a doctor) and the John Gospel (Eagle or Man's spiritual thought born activity into the future ).
To be clear, Man is not and has never been an animal as the above expressions are and have been spiritual activities to which he wives within, in a time progression expressing into space; from the realm of the spaceless.
The gospels of Matthew, Mark and Luke were written by advanced men, or initiates of some degree, who interpreted the Christ being through their particular mystery exegesis. the gospels are not histories and men from these beginnings have looked to the gospels for their spiritual nourishment through the spiritual esoteric effects of these great leaders of mankind.
The gospel of John can be thought of as the only gospel written by a human who experienced the advent and progression of Christ Jesus in time. This gospel of John, the Eagle and the highest who points to the future was written by the "Risen Lazarus" who is now known as John, the author of this gospel, the apocalypse, and other Christian writings.
At chapter 13 of the John Gospel we have the "Risen Lazarus" and please note the change in tenor of the subsequent chapters for from then John, the new Lazarus, is writing. this is aphoristic but a good consideration.
The Churches, in the movement in time, as has the human soul(s) have become immersed within the materialistic ethos and lost sight of the spiritual and the dogma of science manifests to this soul only to the material. this is the nature of evolution, not to be denied, but there is more.
Respectively the Christ Being ,known to the ancients of all nations as the Messiah was appreciated not only in the mystery centers but among the common folk as of the highest of spiritual beings but this consciousness, an atavistic consciousness, has been lost.
The churches and folk now see and relate to Christ Jesus as an earthly Being and event but this event, the event of Golgotha was and is a spiritual event of the high in which the Being, Christ, entered into the body(s) of Jesus of Nazareth at the Baptism of John, the child of Zebedee.
Jesus of Nazareth was an advanced Man who had purified himself through many lives to the highest degree and yet,was a Man for only a man could be responsible and co creator within the Christian ethos. At the Baptism the Christ Being entered into the body(s) of Jesus of Nazareth and became Christ Jesus . Previously Jesus of Nazareth had sacrificed his Ego, or spirit being of the individual man.
This Christ Being, had never entered into the earthly realm , had no karma to complete, and for 3 years walked the earth , was crucified on the Cross and at that time entered as the being of the earth, and became the Spirit of the Earth; thus "eat my flesh and drink my blood".
You and I are spirit/soul beings who work through our physical and life bodies (the earthly man asleep) and as we re spiritual beings likewise the Spirit of Christ, has the physical and life manifestation of the Earth, He is now in the hearts of all men, as guide in the overcoming of death, the work of the future.
Sorry, it goes on , and is an esoteric marvel that cannot be denied.
Knowledge of the bodies of man is in order as physical body, life or etheric body, astral body (sensory) and ego or spirit body(thinking activity). These are four separate bodies which intermesh and we have lost an appreciation of the higher bodies( non material) in the mad rush to materialism, but there is hope.....