Don’t bother retaking the SAT. 2300 is fine for even the most selective schools. Your ECs are fine - not the kind that will make up for a low GPA, but not going to hurt either.
Tell us more about that 3.4: Did you just have a bad semester or year? Were there extenuating circumstances? (The UCs don’t factor 9th grade GPA into their GPA calculation - does this help or hurt?) What percentile are you in relative to your class-mates? Top 25%? If you are at a school that gives few As, it’s possible that you are doing well. You will be evaluated relative to your peers at that school. An upward trend matters here. If your 3.4 is just the result of not having buckled down over the past three years and you are not in the top 10% of your class, your reaches actually extreme reaches. That 2300 could be interpreted to mean that you have the ability but didn’t make the effort.
Take a look at the Common Data Set for each school on your list (google it) and go to Section C. You can chance yourself.