The cheaper school. These schools are both very good with many opportunities.
I don’t feel your cons for UCR are very strong. Outside of HYPSM undergrad doesn’t really matter. And clinical research isn’t super common for undergrads. The only people I know who did it had personal connections (i.e. their parents were doctors).
Also on the prestige factor for UCR, I went to a low tier state school with little if any national prestige/recognition (UCR is about 100x more recognizable than my school). It was the best choice I made in undergrad. I had every opportunity I could ask for without having to fight tooth and nail, did well in classes, had a real good time, and got into my dream med school.