Warpiglet
Adventurer
Radiant Soul adds charisma to spells that do radiant or fire damage. A regular paladin divine smite isn't a spell, so it wouldn't benefit from the ability. Spells like Searing Smite and Branding Smite would though.
drat!
Good catch btw...
Plan B...I want a couple of extra level one spell slots. So, perhaps cleric for a level? Might want to do a few of the (name escapes) spells that do 4-16 and grants advantage and follow up with GFB the following round...