It’ll take time to figure out what vivas look like now.
Old, settled norms of “vivas are about this long” or “vivas have this kind of structure” will be in flux a little. Examiners will have to tweak their approaches, candidates may need to consider things in their setup for the viva, and so on. That might not be a bad thing.
Remember though: the circumstances might change, but the reasons remain the same. Your examiners are there to examine, you are there to pass. You still need to prepare, and while you might need to practise differently – checking tech, being sure of any changes to regulations – the practical prep tasks you’ll complete to be ready will be largely the same.
If you need to, dig deeper into expectations by finding others who’ve had a remote viva. Focus on getting ready just as others have before; there may be new expectations for the viva now, but lots of old ones will remain.