The viva is often framed as the top of the mountain after an epic climb. It’s taken a long time, a lot of work, but finally you reach the summit of your PhD. Some people take the story even further, “it’s all downhill from here, hahaha…”
I think it’s more accurate to see your thesis submission as the summit. The viva comes a little later. The viva is talking about the climb, how you did it, what worked, what didn’t and maybe how it compares to other climbs.
While you’re up at the summit though, pause, look around. What’s on the other side of your PhD-mountain? Where are you going to go next?