The viva is a discussion. It’s not a Q&A. It’s not an interview. It’s not supposed to be combative or about proving who is right or wrong.
Remember that your examiners are allowed to have different opinions to you. They may not agree with a conclusion. They may think that X needs more Y to account for Z.
And that means that you may have different opinions to your examiners. Different opinions don’t mean that someone is wrong. It might mean that – or it could mean that someone needs to think more, explain more, share something else or do something else.
If your examiners ask for a change or strongly suggest something then ask why. Explore more and dig deeper. And do your best, not to prove them wrong, but to engage as best as you can with what they are offering to the discussion.