Hello @Kiran Zende
AccountEnabled status is set to false for accounts created without passwords which applies to external IdP Accounts. Only Local accounts users will get their account set to true during SignUp process.
Setting the AccountEnabled status to true wont work as this is controlled by B2C itself. You might want to create a custom attribute (extension_accountEnabled) for this purpose.
For more information, go through the information on this link which might help.
Let me know if further assistance is required