529 plans will give you tax advantages. I think the limit in 2020 was 24k per child, so maxing it is extremely difficult for most folks. In order to get your state tax breaks, you have to ensure you're using your state's sponsored 529 plan. Iowa's is Vanguard. If the money is used for school, it's tax and penalty free. If it's used for anything else, it's taxed and penalized. The nice thing is that you can transfer the beneficiary though. If kid A decides they want to do community college you can spend what you need there and then transfer the balance to another eligible beneficiary. The new beneficiary has to be related in some manner, I think they let you go out to a first cousin at this point. The most important piece is that you own the account and the monies. If you want to close it up, feel free, but you'll pay taxes on it.
Someone mentioned UGMA/UTMA, your child will own this money from the day it's deposited. There is no transfer of ownership other than when the beneficiary has reached the age of majority (dependent on what state you're living in, usually 18 or 21) then the beneficiary takes controlling ownership of the account. If little Johnny wants to take his money and hit the Vegas strip, that's his call and he's eligible to do so, you can't say squat about it. There are no strings to how the money is used. There are also no tax advantages. Beneficiary will pay long or short term gains on any earnings, you don't get a tax write off anywhere down the line.
Those are the two I know most about so that's where I'll stop weighing in.