USC or UCLA

USC has an actual undergrad business program whereas UCLA does not, and the IB / finance clubs at UCLA are extremely competitive and difficult to get into. I'd say USC would give you overall better chances of breaking in.

I think you definitely need strong internship experience before / during your college years to prove that you are interested in breaking in, since you're getting a bit of a later start. Your GPA is important and it's good that you have a 4.0, but I think work experience is more crucial for you at this point. And doing a lot of self-studying to make sure you're caught up on technicals and the general industry. I hate to say it, and this is not my personal view, but I think people often view transfer candidates in a less favorable light, so you may need to stand out even more among your peers who've been at USC / UCLA since their freshman years.

And even you can't break in right out of school, don't be discouraged. There are plenty of people who grind and land the job they want after they graduate. And the job market will likely have bounced back by the time you recruit.