GCSE's- my dd is delighted not to sit them, she looks happier than I've seen in ages. That said, she did very well in her mocks for which she did revise, and so isn't worried about teacher grading either. Even if teacher grading is used, the results will be standardized with other cohorts/years, so that C will transform into an A. The exam board know how to do this, they do it every year to fix change their results.
University, whoever is in terror of revising and sitting university exams with kids around- don't be, the universities will put in place online assessment so you won't have to go in to take an exam. Yes, kids around is annoying but unless it's a huge amount of exams, it's actually going to be easier and more like coursework, I also expect it to be reasonably generously marked. Again, exam boards will not let an entire group get a grade lower, they will make sure the 2:1's and firsts keep going.
At uni, we are well equipped to work from home for some disciplines (less so lab based ones). Me and my colleagues mark from home all the time, so marking more online assessments will be routine for us. They WILL sort it out though, our uni (RG) is working overtime to sort out exams and assessments in a way to be fair, but not face to face.
Equally, even though everything will be ok for these exams and assessments, I think it's hard to adjust your mind when you have been focusing on this one thing for ages to suddenly deprioritize it.
For SATS, it would have been better had the system not been invented and then we wouldn't have enculturated an entire generation of 10 years olds to start sobbing when they can't take their really pressurized and useless exams at the end of primary (which should be such a lovely time). Perhaps we might all rethink where we ended up as a society, why so many of our children are on exam tread-mills, and whether we might like to do things differently.