The foundation of viva expectations is hearing the stories of others. Statistics and generalisations only exist because people share their experiences.
So ask around before your viva and tell others afterwards.
The questions and structure of your viva are built on what you have done and what your examiners need to dig into during the examination process.
So if you reflect and review what you did and learn more about what examiners do then you can be ready.
Viva preparation is founded simply on you continuing to do the work. A particular focus and perhaps a particular urgency, but more good work that you are capable of.
So do the work!
Your success has you at the cornerstone. Your past achievements and progress are the basis for doing well and passing your viva.
So remember that.