LMU might have more merit potential than Santa Clara. Their STEM reputation has been growing, especially since they obtained ABET accreditation for their engineering majors a few years ago. (Not important for CS in particular, but raises the profile of the College of Science & Engineering overall.) Still a bit of a long shot to get down to 45K but maybe worth a look. Redlands is another to check out - at under 3K undergrads, it may be more the size/vibe you’re looking for.
Southern Oregon U in Ashland is a more LAC-like WUE school. (4500 undergrads) An easy safety to lock down early (rolling admissions) and guaranteed affordable with WUE. They offer a CS majors with both BA and BS options. Definitely has a more laid-back vibe; my d’s friends who went there were very happy. Not really urban-adjacent but Ashland is nice and you can fly into nearby Medford.
Aspiring to CS seems to be sort of a default nowadays for a lot of kids who like computing, but many discover that the deep dive into CS theory and software architecture isn’t as fascinating (or laid back!) as they imagined. What’s the nature of her interest? It can be worth exploring other computation-related majors like data science/analytics, GIS-heavy geography majors, info systems, and so on. Since she likes psychology, cognitive science can be a great CS+psych hybrid. Looking at some even more off-the-beaten-path majors at schools where you know she wouldn’t get into CS could also be worthwhile. For example, the Packaging major at both SJSU and SLO is relatively easy to get into, and it’s a very interesting project-based combination of engineering, design, psychology, and business. Small program with small classes and lots of individual attention; and the employment outcomes are fantastic. She wouldn’t be wasting a shot at CS at these schools by applying, since she wouldn’t get into CS anyway, and it could be an interesting alternative to have in the pipeline in case her CS interest wanes. Bachelor of Science in Packaging | Nutrition, Food Science, and Packaging
It’s not unlikely that she could get into Merced, and the more intimate vibe of the smallest UC might not be a bad thing for her. Merced has CogSci as well as CS. Here’s a parent perspective on the strengths of UCM: A very honest opinion on UC Merced from a UC Merced skeptic - 2022