I had doubts at first, but this has become just the right mix of dumb OP MC fun and hilarious twists like "let's pretend we're the bandits so I can enjoy fighting the heroes", "isekai protagonist gains the power to summon more isekai protagonists - new at eleven: the world is doomed", and "we've got the new demon lord in our party - hey, let's put fighting an empire on the agenda!". This MC is just the right mix of cocky pride and actually being a pretty decent guy, without getting too annoying or edgy.
I've also really been digging the fact that the world has been obviously impacted by past isekai protagonists (even though it's so obviously a ploy to shoehorn in THE ALMIGHTY RICE).
This story knows it's stupid, and it's having fun with it.