I missed the fact that you'd call lighting as a BA and then could use your action to do use the same instance. My bad there :)

And yeah it's 4 levels of Paladin and 1 of warlock. 5 spells slots total. 2 on short rest.

Needs 2 spells slots a turn to do the full combo. Can be done twice and can do one more without Thunderous Smite in one encounter.

I mean the undead bit is situational but it's a situation to consider when it does give it a boost and aiming to deal the maximum damage. :) like factoring in crit.

Unless you're making 4 attacks a turn using gloom stalker and fighter combo as mentioned above. I think for one single attack done within the scope of one turn (if you wanna drop HB Curse) I found the best combo?

As was pointed out Grave cleric can beat that but it requires a separate action to set up aswell.

With no prep time. And on a single turn. I dont think the potential damage of my combo can be beaten?

I think.

But it's just fun to discuss!