Carlovonsexron wrote:energy overload?
But then the process by which Slaanesh becomes stronger isn't really defined either. there's nothing saying (to my knowledge at least ) that slaanesh post meal sleepiness wouldn't have worn off eventually and she wax great and powerful
Slaanesh was glutted out and and sleepy (like the afternoon of Christmas day

) I think there is mention that Archaon has destroyed many worlds as the Everchosen since the End Times which suggests that the Chaos gods do exist in many dimensions or whatever you want to call it in
AoS at least.
However I think you are correct, these days
40k is a separate property entirely with no crossover. No source or anything, just the vibe I get and there is too much that doesn't really add up.
Edit - just to add, excellent video
OP. Love looking into the history of
GW. If I were a rich man I'd be buying so many of the old books.