This is a problem with 5e rather than BG3.
My first 5e character was a lightning dragonic dragonborn sorc, long before storm sorc was even a subclass. I was very quickly disappointed as I learned how few spells were affected; How bad witch bolt is; How fire would have been objectively better in so many ways; How even fewer spells were affected when I realized thunder is a completely different damage type.
Honestly, if it wasn't for the dialog options and being able to cast multiple non-cantrip spells in one turn (contrary to 5e rules) then I would recommend everyone just play wizard instead.
