Actually, I disagree with the premise of your statement:
I know somebody, whose job is considered by most people to be extremely stressful, who likes to say “it’s only stress if you aren’t having fun”
What people consider ‘fun’ (or stressful) is highly individual. @worriestoomuch point about understanding yourself and the environments in which you thrive is the key, and the rest of the quote give some hints as to where that fits for you:
“cut-throat environment” gets thrown around a lot, but is actually not a helpful phrase, and the tag rarely holds up. A lot of schools with that reputation are not seen that way by most of their students, b/c they thrive in the intensely demanding environment, where they have to push themselves to do their best- and they like that. As the Irish say, it’s a question of ‘horses for courses’: you have to run the horse on the right type of course for it.
“poor mental health services” is a judgement: what I think is a perfectly reasonable level of service for a university service may differ from what you think- and typically what will make the difference is whether they have what I want/need when I want/need it. So, define for you what “good” mental health services are, and then you can ask more specific questions (how long to get an appointment, for example, or what types of services are offered)
“supportive culture” is again a judgement that is very individual. Do you mean that teachers are open and welcoming when you come for academic help? do you mean that students are friendly and reach out to support classmates? do you mean that the administration has a lot of support structures that make it hard to fail? There are colleges that are closer to the High School Musical song & dance number “we’re all in this together”, but none of the three schools you list are like that. Some schools seem to appeal to more, hmmm, self-contained? students, others to more, hmmm, social? students.
All three of the schools you list have a lot of highly focused, self-motivated students. It sounds as if you might be happier at an LAC where there is more emphasis on (for lack of a better word) pastoral care. The Colleges That Change Lives group comes to mind, but there are many others.