Hello @tanmai and welcome to Auth0 community!
What’s your project requirement regarding time available to complete the full migration?
Is the gradual migration [user being migrated to auth0 along with their credentials once they log in against a legacy connection) something you want to consider? Please take a look at a similar topic - Is there a way to migrate existing AzureAd users? - #2 by jmangelo
Also:
Please let us know if we can assist you more.