I recently ran into a problem trying to use VS2019 with the TFS2018 vnext build system.
You cannot select VS2019 in the "Visual Studio Build" step, and selecting "Latest" does not use Visual Studio 2019.
On a test server, upgrading the server software from TFS 2018.3 to Azure Devops Server 2019 fixes the issue. Is there a simple work-around that would allow Visual Studio 2019 to be used without affecting the TFS server in a questionable way.
This question extends the question here: Using VS2019 with TFS2018 vnext build system