Check if they say something about being an attack versus something like "DEX save". Attack ones roll against armor class. The other ones use the targets save. If you know multiple it is worth having one be an attack and another against a save. This is because some heavily armored enemies may have had saving throws. This will come up WAY more often than varied damage resists or vulnerabilities.

Cantrips in D&D tend to be kind of shitty (ie miss often or do little damage) until your character has a high casting stat or high proficiency. Unless you get decent items, that's probably going to happen at higher levels.

Leveled spells are often more effective, but burn spell slots, so you need to manage resources.