Hey everyone. So, I was planning a character I want to play for a future campain. I wanted to play a character partially inspired by the game Brutal Legend. I was thinking a Tiefling, back from Avernus, and playing "hellish" (read heavy metal) music with an enchanted lute/citole/cittern that sound like an electric guitar and is used to cast spells.
I wanted to play mostly by using lightning and thunder spell, but sadly bard doesn't seem that great in that regard, so I was hesitating between playing a bard/sorcerer multiclass, to get the musical aspect of the character and some lightning spell from the sorcerer, probably with a blue draconic bloodline, or playing pure of playing a sorcerer and asking my GM to get a musical instrument proficiency and making my instrument my spellcasting focus.
So my question is : is there any advantage to play a bard/sorcerer multiclass for this character instead of a pure sorcerer ? If yes, what level spread would you recommend ? (Don't know yet for what campain I will use this character, but let's say he'll end level 12)