How feasible is it to transfer to these schools as a junior transfer? I do not necessarily know if the policy is different for UC transfers compared to Community College transfers. For context, I have a 4.0 GPA currently after my first quarter at UCSD pursuing a Computer Engineering major.
Well I mean, with a 4.0 there isn’t much better you can do. With interUC transfers, you still have to adhere to similar rules as CC transfers such as GE reqs and major pre-reqs. Regarding private schools, it’s very difficult to transfer into an Ivy. I’m sure each school would have its own preferences regarding what you should have completed by the time you transfer. I mean, you should apply and give yourself a chance, but don’t hold you breath with places like Stanford/Harvard/Princeton/Yale. Maybe you could sneak into a Dartmouth/Cornell type place. I’m not even sure if Harvard accepts transfer apps.
I do know someone who transferred from UCSB to Cornell a few years back so just know that it definitely is possible.
Hmmm well if you want ivy apply to cornell? They have the highest transfer acceptance rate of any ivy (Not saying its easy to get in of course)
Also, If say you did apply to ivies and UCB, I’d definitely suggest UCB- it’s a “public ivy” and if you’re in state will be SO cheap to get that good of an education.
Even though you would be UC to UC transfer if your gpa is 3.8-3.9 (on the safe side?) you certainly would have a good chance to get into UCB. Just make sure you get your pre reqs done and get experience in CS! You will probably need to do at least a couple of ecs that you can get very involved in. I personally don’t know much about CS majors so I don’t really know what kind of paid work/programming/research or anything that undergrads can do, but finding a project to work on with a professor looks great.
ALSO ONE LAST THING, if/when you apply to ucb explain WHY you want to transfer there. Whatever you decide to do, I believe in you 
luckily if you do apply to ivies for transfer they are all on common app too, so hey, you can just apply to transfer to any of the ivies you like that accept transfer apps.
What’s wrong with UCSD ? You have done well academically, so may have a bit more time next semester for social life or clubs or research. With a 4.0, you should be able to qualify for a lot of opportunities at UCSD and have a great future.