First, relax. You’re GPA is fine. As long as you take the most rigorous classes your school offers you’ll be OK. In sports terms you can only play the team in-front of you.
I would take the ACT again IF you’re going to study. A 34 is great but a 35 or 36 puts you in a better spot for scholarships or Honors programs which offer nice perks. That said, I wouldn’t stress about it. Spend time on the essay’s. They’re important.
I’m assuming UW and Minn would be safeties. Apply to both but only if you would attend if you had too. Great options to have. After that you need to look for schools that fit. What size school do you want? Location? Urban or rural? Do you want to co-op? Also dig into the curriculum. Some schools are very different in what they require for core courses and methodologies. URM status will help but I’m convinced that geographic considerations come into play. Schools are always looking to say they have students from all 50 states.
My friend’s son will be a sophomore at ND. He’s in the engineering school and loves it. I think he said that ND has invested heavily in STEM the past few years. Some good suggestions above. Maybe Rice? Georgia Tech, Northeastern and NC State came to mind
The T20 schools on your list are great but are they great for you? Good luck.