In defense of the sorcerer, a Divine Soul Sorcerer has access to a wider variety of spells than Warlock.
The issue with the divine soul is the lack of bonus spells known. The 2024 updates give all warlock patrons in the PHB and most sorcerer bloodlines in the PHB bonus spells prepped but divine soul isn't on that list.
The 2024 warlock can take a strong early lead with pact of the tome at 1st level for access to cantrips and rituals. At second level they have 2 more invocations that can be used on origin feats with lessons of the first ones. So a celestial warlock can add magic initiate from their background and add magic initiate 2 more times through lessons of the first ones to have it from wizard, cleric, and druid.
So a sample might be a human warlock with the hermit background. (+2 CHA, +1 CON). Human bonus feat magic initiate: cleric. Human bonus skill arcana. Hermit feat healer. Hermit skills religion and medicine; herbalism kit proficiency. Warlock skills history and nature. Invocation pact of the tome.
cantrips: guidance, word of radiance; mage hand, minor illusion; prestidigitation, light *the last 2 are swappable
spells: armor of agathys, hex; detect magic
bonus rituals: identify, find familiar
That's a fair bit for a 1st level caster. Use a crossbow for the time being.
At 2nd level add magic initiate: wizard and magic initiate: druid.
Added cantrips: elementalism, message; friends, mending
1st level spells: speak with animals, unseen servant; hellish rebuke
At 3rd level divine soul kicks in for the sorcerer and the character adds one bonus spell and can add a spell from the cleric list. The celestial warlock adds sacred flame, light; cure wounds, guiding bolt, aid, and lesser restoration. The class can add suggestion and light (from the book) can be changed to shillelagh.
At 4th level this build might take ritual caster. This would even the CHA to 18 and add 2 more rituals. I purposefully used rituals with magic initiate because this builds the character up to 7 rituals available that are swappable. A cantrip is also added and eldritch blast is a good choice because it's about to expand to 2 attacks while adding agonizing blast. Another cantrip to consider is truestrike.
Truestrike as a weapon attack already adds CHA mod once. At level 5 it also adds bonus damage and agonizing blast can be applied to the damage. At 6th level radiant soul also adds CHA damage. d8+d6+3CHA starts to be interesting.
4th level can also add misty step.
5th level grants 2 more invocations. I was just mentioning shadow armor and agonizing blast for this level and applying them to truestrike. Defensive duelist gets added later.
Celestial adds daylight and revivify. Add hypnotic pattern.
That's not optimized and there's room to play with the build. The point is the divine soul adds spells more slowly than the warlock gains bonus spells. The warlock can easily leverage invocations for advantages cantrips and rituals, or skills, or other origin feats, or SLA's.
Divine soul needs an update. ;-)