Ppl transfer all the time from CSUs to a UC. It’s basically right below the pecking order of admit selections under CCC. Yes, it’s not #1, but the myth that it’s impossible or almost undoable is massively overstated. Ppl transfer all the time from CSUs. If it’s easier for you to stay at your CSU, you do not have to disrupt your life to get to a UC.
I’m really tired of everyone telling everyone they can’t do it unless they leave their UC or CSU. They’re misreading the stats.