Project failed to build because .NET 5.0 is missing

Hello, @Joshua-Anderson, and everybody else.

I have a VB.NET project that supports each of .NET Framework 4.5, .NET Core 2.1 and 3.1, and .NET 5.0. The first three framework versions for the project built successfully, but the .NET 5.0 version failed to build because it’s missing important files needed to build.

Failed build:
Offending project:

Also, it seems to be using MSBuild and Roslyn version 16.6, which are not compatible with .NET 5.0. Are there any plans to fix this? Or are there any config files that I should edit?