My parents want to give my new baby some money for a savings account. However, if its just going to sit there for 20 years, I’d prefer for it to gain interest/dividends. Is there any easy way to setup a fund that tracks s&p500 and preferably tax advantaged? Or am I better off just investing in the relevant mutual fund.

After more digging, I think the 529 is the way to go.
Also it depends on the state. Utah’s 529 looks neat and you can use it out of state.