@RagavendraDayakar-6627 Thank you for reaching out to us, let me check the best approach/practices of Migrating Root/Intermediate CA to Azure, give me couple of days time to check on this and revert back on CA migration to Azure.
As you asked for alternate solution within Azure, we do have Azure AD certificate-based authentication (CBA) enables customers to allow or require users to authenticate directly with X.509 certificates against their Azure Active Directory (Azure AD) for applications and browser sign-in.
Not sure if it completely replaces your existing PKI solution, would suggest to go through Azure AD CBA documentation what it offers/how it works -
How does Azure AD certificate-based authentication work?
Key benefits of using Azure AD CBA
Let me know if you have any further questions, feel free to post back.