Well, I'm assuming you probably haven't seen the White secondary tiers of these bosses. Notice how all the bosses shown are only the "Common" variants of the bosses as the title implies, and there exists dual tiered bosses that have massive stat buffs.
This is a personal weapons mod I use that isn't currently available. I hastily put it together as a way of using stronger versions of vanilla weapons, which has proven to be a good fit for CHP.