Honestly, how they conveyed the truth of all the speculations is pretty, even to the last page. It has been a real good while since I last enjoyed a reincarnation-conscious read.
This felt, a bit I dunno... Rushed? For such a big reveal and all it all happened way to easily and quickly with everyone just believing each other. Even that "checker" seems like a plot convenient thingy.
Didn't want it dragged out, but wanted proper set up and climax for it
It only feels this way because the standard reincarnation/isekai never ever ever lets characters know about the past, it's always, at best, dragged on and on until the god damn end of the story.