Beginner investor advice

I’m new to investing and have done a bit of research but I’d love to hear some other opinions. I know it’s not much but I’ve basically got $50 to invest per week due to my current situation. I’m currently thinking 70/30 DHHF/IVV. I understand “DHHF and chill” but I think I want a little more exposure to the US markets than what DHHF offers. The plan is to DCA for the next 7-10 years. Also as I’m not investing huge amounts at a time what would be a the best exchange to use. I’m thinking beta shares direct or is there something better for my situation. Thanks!