As you prepare for your viva, consider your thesis as the record of your research.
You followed a method or were guided by a particular reference. Why? What did that give you? What if you had followed another method? What if you used a difference reference?
Reframing could help you to see other possibilities – not better, but maybe not worse. Something different.
Reframing could help you add more evidence for your thinking: now you are even more certain you made the right choice.
This kind of reframing can open your mind to questions from your examiners. They might ask you to consider other perspectives. They will probably ask questions to gain a better understanding of your perspective. The more practice you have before the viva, the more comfortable this could be when you meet your examiners.