Acquire Session State and Latency Issues

I have a solution (ASP.Net Web Forms, AJAX, C#) deployed on Azure App service communicating with Azure SQL DB (managed Instance). Also has Redis as it's session store. Problem we are noticing range from latency issues to a complete stall of the application mostly after lunchtime. One of the errors we see on New Relic has to do with "AcquireRequestState".

Background: The app was hosted on prem and worked like a charm. Since we deployed on Azure, we have had latency issues, service unavailable and session timeouts.

Need more info, let me know. Thanks for the help in advance.

I have implemented New Relic monitoring to show where the potential lag could be. NR shows that the DOM takes an average of 4-8s to process.