Looks like an explicit dependancy on NewtonSoft.Json 13.0.0 rather than 13 and up.

System.IO.FileLoadException: Could not load file or assembly 'Newtonsoft.Json, Version=13.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed'. Could not find or load a specific file. (0x80131621) File name: 'Newtonsoft.Json, Version=13.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed' ---> System.IO.FileLoadException: Could not load file or assembly 'Newtonsoft.Json, Version=13.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed'. at System.Runtime.Loader.AssemblyLoadContext.LoadFromPath(IntPtr ptrNativeAssemblyLoadContext, String ilPath, String niPath, ObjectHandleOnStack retAssembly) at System.Runtime.Loader.AssemblyLoadContext.LoadFromAssemblyPath(String assemblyPath) at System.Reflection.Assembly.LoadFrom(String assemblyFile) at System.Reflection.Assembly.LoadFromResolveHandler(Object sender, ResolveEventArgs args) at System.Runtime.Loader.AssemblyLoadContext.InvokeResolveEvent(ResolveEventHandler eventHandler, RuntimeAssembly assembly, String name) at System.Runtime.Loader.AssemblyLoadContext.OnAssemblyResolve(RuntimeAssembly assembly, String assemblyFullName) at Google.Apis.Json.NewtonsoftJsonSerializer..ctor() at Google.Apis.Services.BaseClientService.Initializer..ctor()