You can work to make your viva environment as helpful as possible for you.
If you’re working from home for your viva, what could you do in the space you’ll work in? How can you be comfortable? What do you need? How do you need to arrange the resources you’ll use?
If you are in a seminar room, when do you need to check the space before the viva? What do you need for your viva and what do you want for it? Can you minimise distractions? And are there things that you need but which you can’t provide yourself, like a flipchart stand or whiteboard?
You probably can’t have everything “just so” of course. You have to do your best. Whether you have a video viva or an in-person viva, make sure you create the best space you can for your conversation with your examiners.