If any of you were wondering, Eve is still the loving worst. Working through beating the Cathedral with all characters now. When I noticed the beam of light later I felt pretty dumb.
My problem was, all three of the times I mentioned an angel room spawned (what are the odds?) after killing Mom's Heart, and it always had a trap door-I assumed that was how you got there, and that Sheol's trap door was spawning a bit to the left because glitch. yeah, I realized this on subsequent playthroughs. How many times have you killed Mom's Heart, BlackFrost? Because after a certain number of kills a shaft of holy light appears alongside the trapdoor to Sheol in the Womb/Utero 2 boss room, and that's how you get to the Cathedral.