No.
What cantrips would those be?
Cantrips gain the extra die at 5th level, just like classes that typically add extra attack. The difference cantrips do not add ability score damage.
4th level is where feats possibly facilitate damage for weapons more than they do for cantrips.
Only because the damage is forgettable, lol. Agonizing blast is what's not forgettable.
Not until 6th or 11th level depending on the cantrip. Or 17th in the case of vicious mockery. Damage cantrips are given as an option for more damage than the lower damage cantrips with added effects but I would argue the added effects are usually the reason to use cantrips.
People don't take vicious mockery, chill touch, or shocking grasp for the damage but they are still useful.
A crossbow does more damage than the average firebolt at low levels. It's 5.5 for the cantrip because there's no damage modifier from ability score. 16 DEX gives the crossbow 7.5 average damage.
Heavier weapons and fighting styles increase that gap. Monks get a bonus action attack by default using a staff as a versatile weapon or fighters use dueling style for +2 damage as examples.
A great sword (10 damage) does nearly twice the damage as the average firebolt, the monk gets DEX bonus to damage on each attack (13 damage total) so starts more than twice firebolt, and dueling keeps the shield and also does nearly twice (9.5 damage).
TWF is an example of more damage but it doesn't take the fighting style or TWF to be more damage.
It's also the ability to attack 2 opponents. At low levels this can drop opponents more quickly than the incoming attacks hit that would have missed from the shields. It's twice the damage for 10% more likelihood to get hit and worth it at the time, and for things like kobolds drops them a lot faster.
The fighting style doesn't scale well for fighters or in comparison to great weapon master or sharpshooter, which is more of the issue.
Gained at 5th level, not 4th. Like the extra die gained by cantrips.
What cantrips would those be?
Cantrips gain the extra die at 5th level, just like classes that typically add extra attack. The difference cantrips do not add ability score damage.
4th level is where feats possibly facilitate damage for weapons more than they do for cantrips.
Perhaps you're forgetting the damage-dealing cantrips like Firebolt and Eldritch Blast?
Only because the damage is forgettable, lol. Agonizing blast is what's not forgettable.
For most builds, cantrips are still better than throwing darts or shooting a crossbow.
Not until 6th or 11th level depending on the cantrip. Or 17th in the case of vicious mockery. Damage cantrips are given as an option for more damage than the lower damage cantrips with added effects but I would argue the added effects are usually the reason to use cantrips.
People don't take vicious mockery, chill touch, or shocking grasp for the damage but they are still useful.
Perhaps you're forgetting the fact that a 1st-level fighter with two shortswords and the dual-weapon-fighting fighting style can deal an average (assuming a dex of 16) of 13 damage at will.
That seems like more than the average fire bolt.
A crossbow does more damage than the average firebolt at low levels. It's 5.5 for the cantrip because there's no damage modifier from ability score. 16 DEX gives the crossbow 7.5 average damage.
Heavier weapons and fighting styles increase that gap. Monks get a bonus action attack by default using a staff as a versatile weapon or fighters use dueling style for +2 damage as examples.
A great sword (10 damage) does nearly twice the damage as the average firebolt, the monk gets DEX bonus to damage on each attack (13 damage total) so starts more than twice firebolt, and dueling keeps the shield and also does nearly twice (9.5 damage).
TWF is an example of more damage but it doesn't take the fighting style or TWF to be more damage.
At the opportunity cost of shield use plus a variety of other weapon and fighting style related stuff, so it's not exactly an apples to apples comparison.
It's also the ability to attack 2 opponents. At low levels this can drop opponents more quickly than the incoming attacks hit that would have missed from the shields. It's twice the damage for 10% more likelihood to get hit and worth it at the time, and for things like kobolds drops them a lot faster.
The fighting style doesn't scale well for fighters or in comparison to great weapon master or sharpshooter, which is more of the issue.