You are not going to find that data by major.
Below is a link for UCI enrolled Freshman Capped weighted GPA and test scores by major. Enrolled data is slightly lower than admitted data and this is the probably the best information you will be able to find. If there is such data readily available, I would have found it by now.
The link above in post # 2 does not break out the data by major only campus.
You can find enrolled data by college for UCSB here: http://bap.ucsb.edu/institutional.research/campus.profiles/campus.profiles.2019.20.pdf
Some general campus info for UCSD: https://ir.ucsd.edu/undergrad/publications/19_20_StudentProfile.pdf
Freshman profiles by campus here: https://admission.universityofcalifornia.edu/campuses-majors/freshman-admit-data.html
The best overall data is the admit rate data in post #2 which can help gauge your chances. I have broken it out in to a table form here: 2019 Freshman admit rates for UC GPA of 3.00-3.39 capped weighted and not major specific:
2019 Freshman admit rates for UC GPA of 3.40-3.79 capped weighted and not major specific:
2019 Freshman admit rates for UC GPA of 3.80-4.19 capped weighted and not major specific:
2019 Freshman admit rates for UC GPA of 4.20 or above capped weighted and not major specific:
**2020 UC capped weighted GPA averages along with 25th-75th percentile range: **
UCB: 4.22 (4.13-4.30)
UCLA: 4.25 (4.18-4.31)
UCSB: 4.17 (4.03-4.27)
UCI: 4.11 (3.96-4.26)
UCD: 4.11 (3.97-4.25)
UCSC: 3.94 (3.71-4.16)
UCR: 3.88 (3.65-4.11)
UCM: 3.68 (3.40-3.96)
Based on your other posts, you are looking at applying as a CS major. My advice is to target a GPA at the 75th percentile or higher. If you have competitive SAT/ACT scores, definitely send them but GPA and test scores alone will not determine your chances for an acceptance.