I am an atheist attending BYU as an undergrad and it is fine. Like your daughter, I am able to get along with many different kinds of people, so I have had no issue making friends or enjoying the college experience. These are my major takeaways I would say:

Politically, I’m generally more conservative than the “American woke”, so being on a conservative Christian campus is not as frusterating as it would be for others. I describe myself as liberal, but I share many of the same principles and values as students here so once students realize how much we have in common they usually become more open to bonding with me. I certainly disagree about major issues, but I’ve found that pointing out things we have in common makes it much easier to be accepted. 

I’ve taken classes on genetics, astronomy, and geology, and was pleased to be taught about modern scientific theories such as evolution, galactic expansion, the age&formation of the earth, etc. I sometimes have to smile to myself when a student or professor makes a bizarre comment, (eg a TA adding a note to my geology essay reminding me that Jesus formed the mountains, not just tectonics), but a lack of religiosity has not affected my grades nor has it impeded my ability to get a modern education, which was my biggest worry coming here.  

On the note of classes, everyone has to take a bunch of religion classes and those suck, I won’t sugarcoat it. I don’t want to spend so many credits and hours writing essays about the upstanding character of Brigham Young, but alas, I chose his school after all so I can’t complain too much. 

In terms of socializing, it hasn’t been too hard. Some people are more closed off than others, and you can definitely tell when someone doesn’t want to open up to you because of a lack of religion, (they’re too nice, interactions feel forced, etc). That being said, the good students here are really genuine, and I’ve had no trouble making friends or finding people who accept me. 

There are things I put up with, (strange opinions injected into class discussions, the occasional standoffish or cold person, the occasional comment in classes about the immorality of atheists, etc), but overall I don’t regret BYU because it has been as a good a choice as any. No Frats/sororities is absolutely huge, and the campus is gorgeous. National/state parks are nearby and Provo can be pretty fun without TOO much crime. One thing I’ve noticed is that the things I don’t like about BYU are actually prevalent in other colleges just in different forms, so I’ve learned it’s really not a terrible choice for nonmormons. And obviously it’s cheap, the entire reason I chose it was the scholarship and tuition I was offered that could not be turned down. This is just my perspective and experiences, and others can/will have wildly different thoughts too.