Disclosure, OP: I went to a small LAC myself for undergrad, after which I got a PhD from an Ivy (currently a postdoc). I also think that students can get an excellent education at either, which is exemplified by the great outcomes at both UCLA and Pomona, so there’s no wrong answer here. Personally I would choose Pomona.
The professors that teach at places like Pomona would have also been competitive for jobs at top research universities (and may have gotten interviews or offers at some) - they have usually done at least one postdoc and have the research chops and publications. If you take a look at the professors in your daughter’s choice of major, likely they have gotten their PhDs from the best programs. (I know that is the case in my field.) They choose to go to SLACs because they want to interact closely with undergraduates and teach small classes. Elite liberal arts colleges have teaching loads that actually aren’t all that different from top R1s (2/2, or two classes a semester) and they expect their professors to be involved in research. Professors at top-notch SLACs usually get small grants from national agencies, so while there won’t be an fMRI scanner or other expensive equipment, there are definitely resources. And at this point in their nascent careers, undergrads don’t need access to expensive equipment or world-class research. They need a patient mentor who is research-active but who is also willing to guide them and teach them how to do the research. SLAC professors are hired on the basis of their desire and ability to mentor undergraduates in research along with teaching.
I am currently at a large public research university and have observed a mix. Obviously the professors at UCLA are going to come from the best places and be doing the best kind of research. I can’t say that the professors seem excited about teaching or mentoring undergraduates on average, but having attended an Ivy for grad school (another research institution) I will say that many of the professors there did care deeply about their undergrads and spent hours mentoring and chatting with them, so there’s just more of a mix at research universities. Many lower-level classes are large but also the majority of students are not going to seek out the professor after class, so I think that a student who wants a close personal relationship with faculty at a large research university can get it if they are willing to pursue it.
I will say that incredible facilities are really nice to have, even as an undergrad. If your daughter is interested in research, having access to good papers and journals and databases is important, and good library instruction can also help a lot (i.e. having librarians who teach classes on citation managers or are willing to help thesis students). I worked in the library of a SLAC doing these tasks, though, so SLACs do have them. A place like UCLA will obviously have a much better library, and potentially better study spaces and computer labs and a student center etc.
I disagree with @ababon that it’s about the maturity level of the student - there are students of all maturity levels at schools of all sizes; given Pomona’s stature I’m pretty sure the students there are also overachieving and highly independent. But I do agree that sometimes there is a value in forming relationships with graduate students. I mentored some undergrads when I was a grad student and it was such an enriching experience for both of us - they asked me many questions about graduate school, which I could answer on a more immediate basis than my PI; I gave them the research guidance that they needed, and I had much more of my time to give than our busy professors. The interesting thing, though, is that’s what made me want to teach at an LAC or some place that emphasizes undergrad education. And I can’t say that most of my grad student colleagues were as interested in mentoring undergrads (in fact, my enjoyment of it made me kind of a curiosity in my department, lol). You’ll get more of a mix at a place like UCLA - many professors are really interested in shepherding people through, teaching, but their primary job is research and that’s where the rewards (tenure, money, stature) lie. But the resources that they have are going to be phenomenal and probably more than you can access at a small liberal arts college.
Anyway, having gone to an LAC I think it’s a pretty ideal environment for college, so were it me I’d pick Pomona! But it really depends on your daughter’s preferences.
Good luck!