Thank you for posting your query on Microsoft Q&A. Currently there is nothing on the roadmap of Azure B2C considering deprecation on HTML templates.
As per latest Developer notes for Azure Active Directory B2C, User experience customization By using HTML templates is unchanged.
However for updated status I would suggest you to stay posted on our Azure Active Directory B2C: What's new and Developer notes for Azure Active Directory B2C for upcoming changes and roadmap.
Thanks,
Akshay Kaushik
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