If your degree goal is PhD, look for funded programs where your tuition is covered and you get a living expense stipend.
If your degree goal is some other graduate or professional degree, consider your career path and likely earnings in relation to the cost of attendance and debt you may have to take.
https://collegescorecard.ed.gov can give you an idea of what graduates of each college, major, and degree level found in terms of earnings, although it is limited to those who received federal financial aid. For example, at SDSU, graduates with a master’s degree in public health had median earnings of $52,733.
If you are looking at a graduate degree, your GPA in the degree is not important, unless you are doing a masters and want to go on to do a PhD or a PsyD. However, if you are unable to get mostly As in any masters program, you should likely not be going on to do a PhD. If you are unable to get a GPA that is high enough for you to graduate, in any program, you should not be in graduate school.
So potential grades are not a consideration for attending any graduate program.
In fact, you should ONLY look at such programs. Nobody should EVER do a PhD which they need to fund themselves, unless they are independently wealthy, very wealthy…
Can’t speak to public health, but the strongest applicants to clinical psych PhD programs will have ~3.8 GPA and significant research experience, so consider undergraduate work in an institution where you can do that. It’s become increasingly common to work for a year or two as a research assistant after the BS/BA before applying to psychology PhD programs. Your PhD should be funded (with the possible exception of a few housed at med schools), although most stipends are pretty lean.
I went to grad school for the exact same thing (I completed my PhD at a hybrid psychology/public health program). I am going to assume that you are a high school student seeking admission to undergraduate college, and you’re asking what undergrad institution you should attend to prepare for graduate school.
The answer is that any of those colleges will prepare you for going to a PhD program, so you should pick the college that you like the best and that is affordable to you. (You’re also making some assumptions about the ease of getting a good GPA across a wide swath of schools which I wouldn’t recommend.)
However, I will say that schools with more robust research programs may allow you to get involved in more interesting and varied research related to your interests. UC Berkeley and UCLA both have excellent schools of public health with professors who conduct research in the area; not only will you have more choices about whose lab to volunteer in, you also will have the opportunity to take public health courses. UC Davis and UC Irvine also have decent good health programs, and at UCSD, you can major in public health.
That said - I went to a small LAC without a robust program in public health and did research that was only tangentially related to public health, and I was still admitted to great programs in the field. So you can absolutely do that from a place like Chapman or Cal Lutheran.