Hi Harsh,
Thank you for reaching out to Microsoft!
You can get the Global admin role assigned to some other account only if you can login with account which has Privileged Role Administrator
This role has an ability to assign Global admin role to any other account within Entra ID.
If you do not have any other account with Privileged Role Administrator, then the only option is to contact support and data protection team to unblock your Global admin account.
If you are the only global admin on the account and are blocked entirely, you can reach out to our support team. You can look into below article to get support numbers depending on your country.
or creating a ticket through a different account: https://learn.microsoft.com/en-us/microsoft-365/admin/get-help-support?view=o365-worldwide#phone-support
similar post: https://learn.microsoft.com/en-us/answers/questions/2129090/how-can-i-assign-the-global-administrator-role-if
Hope this helps.
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