UNC-CH has about 18,000 undergraduates in a state with 10 million population (1 to 555). UCB has about 27,000 undergraduates in a state with 39 million population (1 to 1444). Even with no out-of-state students, UCB would be much more competitive for admission based on the number of in-state students applying.
There are 9 UCs and 23 CSUs to choose from, many of which are not super-competitive in admissions.
UC 4, 5, and 6 year graduation rates tend to be better than predicted by the entering students’ stats.
The main issue is not getting the classes you need for your major; it is getting into your major if it happens to be a popular one.