You wouldn’t be able to double major or switch majors to CS at pretty much any school. The only students that might be able to switch majors would be EECS major students or other related Engineering major students. Engineering and CS are impacted on top of the fact that UC don’t like transfers attempting to switch majors after applying. They try to make it as hard as possible to discourage major switching. Instead I’d suggest getting a CS minor or applying for a Masters in CS.