The other answers have generally good advice, but nobody has addressed a specific question you had:

Kindly share any incident of thesis rejections if you know of any, why it was rejected and how the person finally got his degree.

I only know of one thesis that was completely rejected. In this case:

1. The student had a very weak publication record.
2. The student decided it was time for them to graduate (not the advisor).
3. The procedure for a defense didn't require the advisors signature, so they submitted the form and schedule the exam without their consent. (And initially without their knowledge.)
4. The advisor told them they weren't ready to graduate.
5. At the defense I'm told they couldn't answer even basic questions on the field properly.
6. After a year they were able to try one more time, and nothing changed, so they failed out of the program.

From what you've posted, this is far from your situation. So, while occasion anxiety is understandable, it is probably unwarranted in your case.

The other answers have generally good advice, to address a specific question you had:

Kindly share any incident of thesis rejections if you know of any, why it was rejected and how the person finally got his degree.

I only know of one thesis that was completely rejected. In this case:

1. The student had a very weak publication record.
2. The student decided it was time for them to graduate (not the advisor).
3. The procedure for a defense didn't require the advisors signature, so they submitted the form and schedule the exam without their consent. (And initially without their knowledge.)
4. The advisor told them they weren't ready to graduate.
5. At the defense I'm told they couldn't answer even basic questions on the field properly.
6. After a year they were able to try one more time, and nothing changed, so they failed out of the program.

From what you've posted, this is far from your situation. So, while occasion anxiety is understandable, it is probably unwarranted in your case.

I also know of one case where someone's PhD was found to highly overlap with another PhD in another area with completely different terminology. (Math vs CS) That was awful for everyone involved - in that case they were given more time by the committee to come back and address it, and eventually they graduated.