The typical employer probably would never know an applicant started at a CC - or if they took 6 years to get through and were on academic probation a couple of semesters. Obviously, a job with a background check, say the FBI, is going to know - but they won’t care. It really is about where you earn your highest degree.
The quality of the education varies CC to CC, some have outstanding instructors and rigorous courses while others don’t. So, the knowledge accumulated may - or may not be as good.
As far as alum relations, hard to say. it would be interesting to see some donor number for UC freshman admits vs transfers. Transfers have less time to form a bond, and don’t have that freshman dorm experience that seems to foster a lifelong affinity for a school.