Farming Boss Armor

[Buddel]

I was looking forward to get the Sewer bosses Armor after killing him, after doing it like 3 times, I only received his gauntlets. In the previous game version...
Is there a more effficient way to farm Bosses than making a new Realm and bascally playing the entire game until you meet them again and again and again?

[Sera]

I would assume Plague Versions drop them too, (havn't messed with that to much)

RNG... *sigh*