I do not think that “cumulative GPA” is the most important thing. For many, many very good universities, having a strong sophomore and especially junior year of high school is more important compared to your overall GPA for the first three years of high school. Universities will look at your individual grades. Having a strong upward trend will help you.
Your freshman year might make Harvard and Stanford very unlikely (for undergrad). However, your strong uptrend and a strong sophomore and junior years will help you a lot in getting accepted to very good universities.
One acquaintance of my younger daughter had a similar “really bad freshman year”. She was so worried that I think that she ended up applying to something like 30 colleges and universities. I think that she ended up with at least 20 acceptances (which led to the next problem which was deciding where to attend).
Yes, admissions will look at your individual grades. They will see the uptrend.
I have seen students come back from a lot worse and still do very well.
Also, do not be surprised if a few universities ask for your midterm grades senior year. You will want to continue the good work through your senior year both to help you prepare for university, and also in case any schools ask to see senior year grades.