But we wonder how our tax code gets so bloated.
This is for the first year only. Make the payment automatic when the child's social security card is issued. Make it for all children and do away with the cost of means testing.

Or better. When children get their social security number send the parents a monthly check, or deposit, for $300. Until 18 or 23 if in a school past high school.

That's a pretty big tent right there.

And middle income.

$400k is neither. Plus the administration cost money and throws up barriers.

you file your tax return, it includes your income data, you check the box for your credit, your tax return gets processed and as usual credits are applied and a refund check, if appropriate, is issued.

Using the existing IRS system is the least cost approach.