Curated Confidence
Confidence follows from honestly reflecting on your work and achievements. You have to explore and remind yourself that you have done well. To build confidence for your viva you can look back over your PhD and see the effort you’ve invested and the progress you’ve made and hopefully feel good.
It won’t help to hold on to everything though.
You learn from your mistakes and setbacks, but don’t bring those in to the gallery of recollections. Like a curator, pick and choose which things to focus on. You can find confidence by focussing on what has helped you the most or the work where you notice the most growth.
You don’t need to try to remember everything to find confidence for your viva. Explore your PhD journey, then arrange a gallery of the best bits. Curate your confidence for your viva.