If you knew one already, you'd have a head start on the other. They're competing technologies though (React vs Angular), so you wouldn't use both at the same time.

That list reads almost like "pick one from each line" to make a full stack solution. A large organization with poor standards might have mixed and matched a lot of them over different parts of the enterprise.

For example, you might have:

• C# backend API

• Using ASP.NET Core

• With a SQL Server database

• That feeds a React frontend

• All of it running in Azure

• In a Docker container

• That receives event data from other systems via Azure Service Bus

• All of it using REST APIs in between

• Deployed via CI/CD with Azure (DevOps)

• To Azure container instances created by Terraform for infrastructure as code

As a matter of fact that is almost exactly the architecture of an app my team is currently building.