If your daughter is such a good student that she could even get into Duke and Princeton, then there should be many wonderful schools which she can really like (or even love) that will provide some merit money. They may not be quite up to Princeton’s ranking, but few are, and she may love them better than UF. Maybe let her pick one of her top reaches, with the understanding that she’d have to get X amount of money from it to make it work, have UF be her safety (if in fact for engineering it would be a safety) and then find 5 or so schools where she would reasonably be expected to get some merit/scholarships. Once again, engineering is often harder to get into than other schools, so keep that in mind as well. But there are thousands of wonderful schools out there and definitely some that share whatever vibe/characteristics of Princeton/Duke she feel in love with.
I echo what others are saying - so not worth giving to one child and not the other, and definitely not worth (IMO) to dip into retirement funds to pay for a school when other great ones would be much cheaper. As the parent of a college junior, I’ve seen the stress parents feel 2 or so years in when the prices have gone up and now they have another student entering college. It ain’t pretty…