Moon Lord, overall. Empress of Light doesn't pelt you with as many projectiles from as many different angles as the Moon Lord does, and Duke Fishron isn't that durable post-Golem (I actually think he should get a health buff, no idea why he has less health than Empress). Moon Lord has so many tiny projectiles that are almost perpetually on the field, and if they have any pattern to them, then it's substantially harder to notice than EoL and Fishron.