If you want to transfer, it’s best to go to a CCC. It’s incredibly difficult to transfer between UC campuses. Not impossible, just very difficult, especially to UCB as a STEM major.
If you’ve decided to go to UCSC and transfer to Cal, just make sure you keep a high gpa, plan out taking the necessary courses for your major in advance, have enough units, and so forth. Assist.org is a great resource to see which classes articulate.