I see that the errors are:

/Users/runner/.nuget/packages/microsoft.net.test.sdk/17.14.1/build/netcoreapp2.0/Microsoft.NET.Test.Sdk.targets(4,5): error : Microsoft.NET.Test.Sdk doesn't support net6.0 and has not been tested with it. Consider upgrading your TargetFramework to net8.0 or later. You may also set true in the project file to ignore this warning and attempt to run in this unsupported configuration at your own risk. [/Users/runner/work/pythonnet/pythonnet/src/embed_tests/Python.EmbeddingTest.csproj::TargetFramework=net6.0]

Is not something I Implemented... so i didn't commit my changes at the .csproj, but i think is enought to edit Python.EmbeddingTest.csproj tag:

<PropertyGroup>
    <TargetFrameworks>net472;net6.0</TargetFrameworks>
  </PropertyGroup>

to latest .NET LTS:

<PropertyGroup>
    <TargetFrameworks>net472;net8.0</TargetFrameworks>
  </PropertyGroup>

Link to MS versioning:

https://dotnet.microsoft.com/en-us/platform/support/policy

Am I missing something?

Can i commit the project edit?

Sorry for the mess with the build. It's not quite as simple, I'm looking into updating our CI to use .NET 8 and uv, see #2612 and #2520. Once these are through, I'll revisit your PR.

#2639 should do this without trying to parse the version. Thank you for your effort!

Ok, i see the #2639 commit and it should work.
Just another cent:
MemoryStream() is disposable, i think is better to dispose of it after use to avoid memleak before returning BinaryFormatter()

Thanks, I'll change it accordingly. For MemoryStream in particular, Dispose effectively only "closes" it via a boolean, but it's still better style to do that here.