Based on https://www.universityofcalifornia.edu/infocenter/freshman-admissions-summary (click Admit Rate and HS GPA), for 2019, the admission rates for applicants with weighted-capped GPA >= 4.20 were:
- UCB: 38%
- UCD: 87%
- UCSC: 85%
But note that CS is generally a more competitive major than the campus overall. However, for UCB L&S CS, you would be applying to L&S, which should approximate overall admission rates.
Several of the UCs are quite likely, but it may be risky to say that they are 100% chance safeties, due to consideration of subjective factors like essay reading, increased competition for CS, variation across years (competition level seems to be increasing generally), and uncertainty due to COVID-19-related factors.