Slight spoiler warning:

Same for me. I put it down for a few days after failing Mantis Lords and Soul Master and getting salty about the bench placements, but after watching this video on why the Mantis Lords are fantastically designed , I picked it up again and start to really enjoy it – winning both of these boss fights in two attempts. Before engaging them again, it was worth exploring more and getting stronger. The game doesn't communicate well how strong you currently are (e.g., by not having health bars for the bosses). The best clue was to see how well you can score against the standard monsters in that area.