I think Warlock is confusing for how the gain and expend spellslots. It's pretty different than all the other casters. Their spell options are a lot more compressed, not just from the spell list but how the spells are cast and then replenished on short rest. The way the encounters are designed and the whole long resting mechanics of BG3 just make it harder when comparing with Cleric, Wizard, Sorcerer, Bard, Druid etc.
I feel like if there were a couple other caster classes that worked in a similar way for their spellslots, it would be easier to get the head around, but that's more of D&D gripe than a bG3 gripe. For BG3 they is some wonkiness when multiclassing Warlock with other Spellcasters.
