Pretty standard fare for a Cleric/Sorcerer. Throw a water bottle or quicken cast Create Water (if you have no time to prepare the battlefield), then cast lightning spells for massive damage. Maximize against priority target(s). Low Dex is actually quite advantageous in this case, as we want to go later so one of your martials can throw some water around first. You can (and should) wear heavy armor and shields, which will make you reasonably tanky, for a full caster!
In truth, your Race choice will not make or break this build as there’s nothing in particular we’d want. Druegar/Deep Gnome/Drow would work well due to Superior Darkvision, which will help, but anything with Darkvision is good enough. I simply picked Drow as a default option as having darkness on tap is never a bad thing
Overview
Background
Noble
Race
Drow
Overview
Class
Sorcerer
Skills
Arcana, Intimidation
Stats
STR
DEX
CON
INT
WIS
CHA
12
8
14
8
16
16
Leveling Guide
Level
Take
1
Sorcerer: Light, Ray of Frost, Shocking Grasp, Fire Bolt; Chromatic Orb, Shield; Storm Sorcery
I think dropping the 2 strength and going to 17 cha for an easy 18 from Auntie Ethel's boon. You can pump up wisdom more as well by the end. IF you really want that 12 strength just drink the potion for perma +2 or like an elixer.
you want initiative lower so you can guarantee someone gets to act and throws some water at the enemies first. That and it does absolutely no harm for you if you start as a surprise round.
is the 3rd lvl cleric worth it losing a the 10th level of Sorc...I doubt it..just for spiritual weapon and aid and shatter vs ssorcery point and a lvl5 spell slot and a metamagic feat..unfortunately no chain lightning in this build..but you can only get that with lvl 11 sorc