Check my response below. Can you also confirm do you have any plan to enable jsreport to store templates in Azure Blob Storage with managed identity?
Do you experience the same on the latest? I tried with 4.5, 4.6 as well
Do you have the app and the file share in the same Azure region? Yes
Have you tried the premium low-latency file share layer? I verified with 'Premium' tier storage account. I can see no difference in performance.