Not to disagree with your broader argument, but to deny Varg's involvement in Satanism in his early material is not the route to go.
From Charontapos zine, 1993:
"Morbid Angel are fake satanists. Deicide is Black Metal. By being commers (sic?) they twist and pervert most possible most souls Black Metal isn't underground. Black Metal is religion! Satanism!"
"Black Metal is not a style of music, it's a style of existence! "Church of satan" bands play White Metal!"
"As a satanist I prefer to kill C.O.S. followers as they are the good ones. Satanism is the worst way. The path of evil. The path of misery."
"When you mean bands like Immortal, Fester, Perdition Hearse, Emperor or Thyabhorrent, they aren't Black Metal bands. To be a Black Metal band, you have to worship the dark lord, and exist purely for him! Only Mayhem, Burzum and Darkthrone play Black Metal. Our proud black trio of Norway."
And of course various other more vague references to "evil" and "darkness" directly correlative to being the antithesis of God, goodness, etc.