Set and forget growth ETFs

Hi All,

I am kinda new to investing. I am looking to put money in long term growth ETFs which I plan to invest and forget for my 3 years old sons future. Currently, I am investing in FXAIX on a monthly basis.

I was looking into VUG, SCHG and QQQM. Can I invest in all 3 at once or are they the same? Also, open to more recommendations. Thanks in advance.