Resolution of Microsoft.Net.Http.Headers assembly version 2.2.0 versus 6.0.0 depends on seemingly unrelated package references - asp.net-core

Question

While trying to use HeaderNames.XFrameOptions, I found that it works in one of my projects and fails in another. Both are targeting .NET 6.
In my app, I need to work with the X-Frame-Options HTTP header. When possible, for maintainability reasons, I try to evade specifying constants for such standard strings myself, relying on standard constants instead. For this header's name, there is HeaderNames.XFrameOptions, available since ASP.NET Core 3.0.
By navigating to the class's implementation in VS, I found that the project where it works uses version 6.0.0.0 (.NET 6, x64) of the Microsoft.Net.Http.Headers assembly:
C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App\6.0.12\Microsoft.Net.Http.Headers.dll
The project where it does not work uses version 2.2.0.0 (.NET Standard 2.0, MSIL) of the assembly:
C:\Program Files\dotnet\sdk\NuGetFallbackFolder\microsoft.net.http.headers\2.2.0\lib\netstandard2.0\Microsoft.Net.Http.Headers.dll
The working project is the main project of my console app and the broken project is a library in the same solution, directly referenced by the console app.
When I looked into the broken project's obj\project.assets.json, I found that Microsoft.Net.Http.Headers is really used in version 2.2.0 and it is referenced by Microsoft.AspNetCore.Http.Extensions/2.2.0, which is also used in the broken project.
I used that info to reproduce the failure:
dotnet new globaljson --sdk-version 6.0.404 --roll-forward disable
dotnet new console -f net6.0
dotnet add package Microsoft.AspNetCore.Http.Extensions --version 2.2.0
echo "Console.WriteLine(Microsoft.Net.Http.Headers.HeaderNames.XFrameOptions);" > Program.cs
dotnet run
C:\Repos\playground\Program.cs(1,58): error CS0117: 'HeaderNames' does not contain a definition for 'XFrameOptions' [C:\Repos\playground\playground.csproj]
The build failed. Fix the build errors and run again.
I tried adding all the packages referenced by the working project to the repro project and it fixed it! By elimination and following the dependencies of the last remaining project, I found that the fix can be achieved by adding just a single package (AspNetCore.HealthChecks.UI.Client/6.0.5):
dotnet add package AspNetCore.HealthChecks.UI.Client --version 6.0.5
dotnet run
X-Frame-Options
I see that AspNetCore.HealthChecks.UI.Client references the Microsoft.Net.Http.Headers assembly version 6.0.0.0, but directly, as an assembly, not as a NuGet package. Sadly, the latest packaged version is 2.2.0.0.
How can I make HeaderNames.XFrameOptions work in both my projects at the same time? Is installing an irrelevant package like AspNetCore.HealthChecks.UI.Client the only solution? And is there a more straightforward way to diagnose such assembly resolution issues?