Warwick did well last year partly because, unlike some other universities, the vast majority of courses did some face-to-face teaching whenever they were allowed to. Some departments did all teaching except lectures face-to-face.
There is inevitably variation between departments and courses in terms of what is possible.
Small departments that just need a room somewhere to teach in (for example, Philosophy as referenced above by @pourmeanotherglass) are able to, and should be expected to, deliver the majority of their teaching face-to-face.
Big departments, those that are very dependent on large lectures, and those that require specialist facilities face greater difficulties and will end up having to deliver less face-to-face teaching. There are not enough rooms, staff or actual existing time for them to turn all their teaching into small group teaching.
This is why Maths (a big, large lecture dependent course) will have more teaching hours online, and Life / BioSciences (the course of @Daisysway's DD) is particularly badly hit because it is a big course, that has usually had a lot of large lectures, and it requires specialist facilities rather than just any room someone can find in the university (and, I think, it is not taught on central campus, further limiting their access to centrally timetabled rooms).
Universities are trying to prevent rapid transmission of Covid through their student and staff population. Students being vaccinated will help, but vaccinations are not 100% effective in preventing people catching Covid.
Even though they may not become terribly ill, students who have to isolate with Covid will be confined to their rooms and will lose both academic and social interactions. Some universities will provide online teaching for those on isolation, others will just expect students to catch up as best they can. Staff who catch Covid will not be able to teach face-to-face and may be unable to teach at all. University terms/semesters are short. Missing a couple of weeks can mean missing a significant part of a module.
In the worst case scenario (but one that all universities are planning for), Covid cases become so high that face-to-face teaching is no longer feasible or even a local lockdown is imposed. In that case all students risk being confined to their rooms again for an indefinite period. No university wants that, and they are taking the steps they consider appropriate to avoid it.