@Arunava Dey Welcome to Microsoft Q&A Forum, Thank you for posting your query here!
As your are looking for Low latency, real-time access & reliable setup, I would suggest you to reach out for Microsoft Consulting Services, so an Architect can help you design environment based on your requirement.With above suggestion, considering the details you have shared, if you are trying to sync data from On-Premise to Azure and have realtime access to data, Azure File Sync is best option. But, the cloud end point of AFS can be only a File share in Azure. As CDN can't be enabled on File Storage, you may not be able to use CDN(Not supported unless there is some sync mechanism between File Server and the actual supported source like Storage Account)
However, if you are using AFS and using file share as cloud endpoint, you can mount the files in different services & build another solution to get the files from that specific file share
Additional information : Azure on the Cheap - Azure Storage Static Website and Azure Front Door
Azure Frontdoor vs CDN.(Compared to CDN its bit expensive) It allows a maximum connection timeout of 240 seconds, but if you're write operations are chunked, it shouldn't be a problem.(For blob)
Hope this helps!
Kindly let us know if the above helps or you need further assistance on this issue.
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