My elder DD did 3rd year abroad. She went to Switzerland for French and then Italy. She went to universities.
The students get briefing meetings here. It does suit confident students best and getting jobs these days can be problematic. DD was told some jobs were not acceptable to the university in that they were not sufficiently varied in learning the target language or rigorous.
At DDs university it was fairly well known some of the French state universities (not the Grand Ecoles) were iffy but you are not marked on what you do in class at the foreign university. Your home university normally sets the work they need to complete. Your DC may have to take the exams at the foreign university but not necessarily pass them so check what the uk university actually wants. If the lectures are not great it may not matter.
If they offer a university that has accommodation, go for it. It saves the angst of looking. If not, travel with them if they lack confidence and haven’t sorted anything out.
There is a good resource in the web site Third Year Abroad where you can read up about universities and countries and get advice from students who have been.
It is not terrifying if you plan. Apply for accommodation early (do not miss deadlines) if it is available and read up as much as you can on the university web site regarding exchange students, induction, where to get help and accommodation.
Where is your DD expecting to go OP? Some universities are brilliant and others less so but it’s a great experience for most. Universities can be huge. The one DD went to in Italy had 88,000 students and large lectures are common. They don’t do seminars. They do chalk and talk! The culture can be quite different but it’s part of the experience.
If I can be of further help, let me know.