Fun & Effective multi class for storm sorc?

Starting my third playthrough after a long break and decided to do Honor mode for the first time. I’ve spent hours trying to decide on a build that would be fun to play as well as strong enough to carry me through this difficulty as I’ve only played normal previously. So far, I know i want to build a caster focusing on lightning and frost (because of the double wet damage) and it just sounds really cool.

Does anyone have recommendations for multi-classing this to make it stronger or mor enjoyable? I have a feeling i might feel a bit underpowered if i go pure storm sorc. Would draconic ancestry blue dragon work better as a subclass?? Im not really good at minmaxing and i waste so much time not knowing what to choose so any advice is appreciated!