Did anyone worked on Azure AD with WebAPI (.Net Framework 4.8)

For Azure AD authentication and authorization using ASP.NET Web API on .NET Framework 4.8, you can refer to the following Microsoft documentation:

1. Authentication Scenarios for Azure AD
https://docs.microsoft.com/en-us/azure/active-directory/develop/authentication-scenarios

2. Authentication and Authorization in ASP.NET Web API
https://docs.microsoft.com/en-us/aspnet/web-api/overview/security/authentication-and-authorization-in-aspnet-web-api

3. Authentication and authorization for Azure App Service and Azure Functions
https://docs.microsoft.com/en-us/azure/app-service/overview-authentication-authorization

You can also refer to the Azure Active Directory Authentication Library (ADAL) for .NET, which provides a set of classes for using Azure AD authentication in .NET Framework applications.

Azure Active Directory Authentication Library (ADAL) for .NET
https://docs.microsoft.com/en-us/azure/active-directory/develop/active-directory-authentication-libraries

This article is best choice for your need:

https://www.c-sharpcorner.com/article/enable-azure-ad-authentication-using-net-5-0-web-api/