Reset
Viva prep can be an opportunity to reset after the stress needed to get your thesis submitted.
Rather than focus on the work you’ve done you can focus on the work you will do. Rather than focus on how you feel about getting your thesis done you can focus on how you want to feel for your viva. And instead of focussing on worries or stresses about whether you’ve done enough you can focus on the contribution you have necessarily made to get this far.
Viva prep can be a reset. It doesn’t change what you’ve done or what you need to do.
It simply allows you to keep going.