that's called the transfer admission guarantee (TAG) program, and it's a fantastic opportunity to reboot a mediocre academic record.
however TAG does not confer eligibility into a number of STEM (and STEM-adjacent, like medicine) programs within many highly competitive departments at the UC system.
For example the neuroscience programs at UCSD do not automatically accept TAG applicants, you have to be qualified by the program's own rubric regardless of securing a TAG spot for the school itself.
Yes, it seemed the G is not as guaranteed as is used to be. I had an interesting chat with a current UC Berkeley student trying to get into computer science department. They have a few classes that you need to do well in to get accepted internally. She was taking one of the classes for the third time, having dropped the course the first two times once she realized her grade was not high enough.
At Berkeley, this depends on the major. If you're accepted to the College of Letters & Sciences (which houses degrees such as Physics, CS, Math) with an intended major, you're actually undeclared when you start out.
Once you complete your lower division prerequisites passably (typically after two or so years), you can then declare your major as a CS degree.
This isn't the case for College of Engineering which houses the EECS program (while sharing the same department as CS, confusing I know), wherein admissions are more selective, but you don't need to declare your major. You also have the advantage of already being in the program, which helps with registering for courses (especially upper-division courses, which typically only have a small number of slots reserved for non-majors).
however TAG does not confer eligibility into a number of STEM (and STEM-adjacent, like medicine) programs within many highly competitive departments at the UC system.
For example the neuroscience programs at UCSD do not automatically accept TAG applicants, you have to be qualified by the program's own rubric regardless of securing a TAG spot for the school itself.