You have no choice about having a viva or not. No real choice about who your examiners will be. No choice about how they feel or what questions they ask. No choice about how much time you’ll have after submission to prepare. You probably have no choice about how a question will feel when it’s asked.
But you can choose to submit your thesis. You can choose to think about potential examiners and give suggestions to your supervisor. You can choose to prepare, you can decide how you’ll spend your time. You can choose your mindset. However a question feels you can choose to answer as best as you possibly can.
You can choose to go to your viva as ready as you can be.
Make your choice.