I finished all the endless dungeons back in October when I played the game originally, that's actually the save I have on Itch.io.
I don't have discord and I'm not sure about discord with screen readers, but I don't mind playing through again as it's been a few months.
Spoilers ahoy for finishing endless dungeons!
When I played through last year, the only reward for finishing all the endless dungeons was viewing of the leader board, sadly there wasn't really even a congratulations message or the like, much less anything like unlocking a cheat's section or some uba special production item or similar. I hope there is something more this time around, or is there some effect on chapter 3 if you finish all the endless dungeons?
If it's just the same viewing of the leader board, then I might just forget the endless dungeons this time.