there community voted on patreon for endgame difficulty as skulls like in Halo instead of a New Game+ type of end game. So currently there is nothing to do like you want, apart from tweaking your save file. It's in appdata
Hi, I've encountered the same issue as the author of the question. I've cleared all the locations, defeated the Mantis, and encountered the Mothgirl. However, she doesn't appear in the sidebar, which may be a bug. Or does she appear in items?