ACTUAL GENUINE ENDGAME AND ENDING SPOILERS:
the final boss was super fucking lame. they literally just reused radiance, pretty much every attack she does is either reused from radiance or reused from another boss in silksong, it's fucking pathetic. extremely boring fight since i already did it back in hollow knight, extremely boring setting of just "dark room with black background" like she's just some random miniboss in a cave, complete nothingburger of a character whose motivations are "me want child" and that's it. they also expect you to feel bad for lace after her second fight (which was 100x better than the final boss by the way) even though she showed up one time 20 hours ago and then did and said nothing for the entire game.
anyway, the whole thing just ends on a wet fart. super disappointed, it feels like they were rushed as hell with this even though the game was in development for seven fucking years. maybe the "true ending" is better if there is one, but i'm certainly not motivated to seek it out after that boring shit.