Note: this is not optimized, but I’d consider it a viable Cold Sorc. If this is an AL character, then XGTE is your +1.
Race: Variant Human, Elemental Adept (cold) feat. This will boost cold damage & let you ignore resistance. Put your highest stats in Charisma and Dexterity.
Background: Consider Sailor or Outlander to add to the elemental flavor of the character.
Sorcerer Archetype: Dragon type, Silver or White. This will add your Charisma mod to cold spell damage once you reach level 6.
Spells: Just bring the Cold. Spells marked with * let you pick Cold damage.
Cantrips: Frostbite, Ray of Frost
1: Chromatic Orb*, Ice Knife
2. Dragon’s Breath*, Snilloc’s Snowball Swarm
3. Tidal Wave (thematic, not cold)
4. Ice Storm
5. Cone of Cold
6. Investiture of Ice
The selection of ice-related spells drops off fast, especially at higher levels. You might also consider multiclassing to something like Warlock, or a higher Strength build to be a Paladin of Cold Vengeance.
[edited to add SSS at lvl 2]