UC Selection need advice

Hey,
I’m an incoming transfer student majoring in applied math and also finishing up pre-med classes. I’m deciding between UC Davis and UC Berkeley. My post-college goals are to attend medical school and join the Navy. However, this decision is harder than I thought and I need some input, preferably from current or former students.

For Berkeley:
My two biggest concerns is finding good housing and fitting into Cal culture. Coming from a CC, I’ve heard horror stories that Cal is so competitive to the point where it’s toxic. Has this been the case for others? Also, how hard was it to find your “clique” per say.
Also,
1a) How hard is it to switch majors within the same college and in between colleges?
2a) Have any former students found Berkeley’s “prestige” significant in their careers?
3a) Is the political climate there as toxic as it seems?
4a) As a math major, would it relatively easy to finish up my remaining pre-med courses, (Just chem left).

For Davis:
1b) How hard is it to switch from an applied math major to an engineering major? & just switching in general.

2b) Best place to live?
3b) How difficult is it to find a single occupant studio/apartment?
4b) Same question as number 4a above.
5b) Is double majoring relatively easy as well? (As in being able to take the required courses and not delay graduation).

@kimjongtim you might receive more responses if you post in the Berkeley and Davis threads.

@lkg4answers It’s fine now. I was able to ask people outside this.