Hey @kaushivari,
I have not gone through extenstion, however there has been recently a conversation thread about a person being refused during extension. We suspect that they went through a wrong home office process and applied for a “switch to Global Talent” instead of exstending an existing visa. More here VISA Extension under global talent scheme refused
So make sure that you read Home Office guidelines carefully and check with a lawyer if you have doubts or special circumstances.
Herman.