The biggest difference from a similar role in secondary school is that in HE your students are adults: you cannot involve parents in discussions without the student's express consent. Also, students are responsible for their own accommodation, food, etc. and social services have no obligation to make sure they have food & shelter as long as they are competent to make decisions on their own behalf.
You will almost certainly encounter students who are failing courses, possibly not attending, engaging in risky behaviours, unable to feed themselves, and possibly even homeless, and who refuse to allow you to contact their parents.
Mental health problems are rife, but you will already be familiar with this from secondary school. The impact of students' mental health on their flat/housemates will be something you also have to deal with, though. You may well have students who are unable to engage fully with their course because one of their flatmates is self-harming, threatening suicide, etc., or behaving in a way that disrupts everyone else's study.
Depending on the institution, you might have students who either don't want to be on their course or don't want to be at university at all, with decisions about course choices having been made for them by family or under excessive influence from school. Even where options to change course exist, some students will leave decisions much too late.
Especially after the disruption to schooling caused by Covid-19, many students will find coping with assessments (exams, in-course assignments with deadlines) very difficult to cope with. There won't be the same kinds of reminders to submit assignments on time, or very much timetabled preparation for exams.