(almost) one-shotting Yurgir and taking on Merregons with magic club

so this is a fight that i'd usually avoid, and just let them kill themselves with persuasion check(if i am to kill them). but whole point of this run is to test magic club myself so i decided to take the fight. with some guaranteed crit, i could one-shot Yurgir for sure but i just decided not to(i was too lazy to get executioner buff, or actually im saving it for myrkul. and no illithid skill at least for now). even though i saved the crit buff, my first smite left him only 1hp. and i found out there are 2 more bludgeoning damage of magic club. it took long enough i found out later that divine smite deals extra 1d8 radiant damage to fiend and undead. i think its plausible enough to say that extra 1d8 radiant damage is the source of 2 more bludgeoning damage here. i had to right click and kill him cuz things get very bad if he throws 4 grenades at me. u already got plenty of glitches n shit when u play solo honour mode anyway. this is one of few fights where darkness doesnt help. since they all have devil's sight. except displacer beast.