You can afford a little break at submission. In most instances, even if a candidate has an idea of their viva date, it won’t be confirmed at the time they submit their thesis.
When you submit you have time. Plenty of time to get ready, but also plenty of time to relax. Rest. Take time away from the work you’ve been doing to get your research finished and your thesis ready.
Pause, for your own sake. You have to look after yourself so that you can get ready.
A little down time will help in the final days and weeks leading to your viva.