@Vipin_Gehlot The TXT record does nothing on its own, as there is no automated system.
I made a feature request for it to automated back in late 2021, you can “like” it here:
https://answers.netlify.com/t/fix-another-site-is-already-using-this-domain-self-service/46443
Currently you need Netlify’s staff to manually do the check/removal.
Because of this, you will generally receive faster assistance by using the support form.
Go to https://www.netlify.com/support/
For ‘What kind of help do you need?’
Select ‘Another site is using this domain’
Then provide the relevant details, (and perhaps a link back to this thread).
Netlify’s team will then respond to you via email.