Looking at add 3rd ETF to portfolio!

Wanted to add a 3rd ETC to my brokerage account. Currently I have QQQM/SPMO at 50/50. I have some individual stocks for my riskier plays, but over looking to add a 3rd ETF to anchor my brokerage account which is in Fidelity. Any advice is great! Thank you I’m 36 years old if that helps