The simplest definition of what you need to pass the viva: enough stuff.
Enough of a thesis. Enough results or findings to write up. Enough data. Enough work.
Enough papers read. Enough knowledge in your brain. Enough talent built up through your work.
Enough confidence to stand up to any nerves. Enough self-belief to know you have enough.
There will always be more you could do, more you could learn, more you could write, more you could do to prepare. But you don’t need more. You just need enough.
If you have any doubts then ask others for help. Ask your supervisor what you need. Learn about viva expectations. Take time to get ready.
When the time comes you will realise that you have enough of everything you need to succeed.
You probably had it for a long time.