VS for Mac unable to add .NET Standard NuGet - xamarin.forms

Question

I have encountered a weird behavior with VS for Mac. This is how I repro it:
Built a .NET Standard 2.0 NuGet package using VS2017. Package is called "MobileApps.Auth 1.0.0"
Pushed the NuGet to our company NuGet server
Switched over to the Mac and launched VS
On the Mac; Built a Xamarin Forms app (shared project is also .NET Standard 2.0)
Added reference to the .NET Standard 2.0 NuGet
ERROR:
Package MobileApps.Auth 1.0.0 is not compatible with netstandard2.0 (.NETStandard,Version=v2.0). Package MobileApps.Auth 1.0.0 supports:
- monoandroid81 (MonoAndroid,Version=v8.1)
- xamarinios10 (Xamarin.iOS,Version=v1.0)
I have zero clues as to why the NuGet would support monodroid81 and xamarinios10. It's a .NET Standard 2.0 library that reference Xamarin.Forms.
If I instead remain on the PC and run steps 4 and 5 in Visual Studio 2017 all is peachy.
This smells like a bug in VS for Mac. Has anyone else seen this?
Overall, having spent a few days building NuGet packages, based on .NET Standard 2.0, both on the Mac and PC I get the overall feeling this doesn't really work on the Mac. The reason I built the NuGet on VS2017 is because NuGet packs built on VS for Mac includes all kinds of facades that causes msbuild to fail due to conflicts (same identifiers found in multiple referenced assemblies).
[EDIT 1]
This is the NuGet layout when package built on VS4M:
_rels (empty folder)
[Content_Types].xml
lib
netstandard2.0
MobileApps.Auth.dll (my lib)
(+ 113 other dlls)
MobileApps.Auth.nuspec
package
services
metadata
core-properties
5bd1f861cd8a425f854c073a4a5f3e0e.psmdcp
And this is the NuGet layout when built on VS2017:
_rels
.rels
[Content_Types].xml
lib
netstandard2.0
MobileApps.Auth.dll (my lib)
MobileApps.Auth.nuspec
package
services
metadata
core-properties
5bd1f861cd8a425f854c073a4a5f3e0e.psmdcp
The difference is that VS4M includes 113 extra dlls in the netstandard2.0 folder while VS2017 doesn't. How can I control that?
[EDIT 2]
This is the .nuspec from within the .nupkg, built with VS4M:
<?xml version="1.0" encoding="utf-8"?>
<package xmlns="http://schemas.microsoft.com/packaging/2013/05/nuspec.xsd">
<metadata>
<id>MobileApps.Auth</id>
<version>0.1.1</version>
<title></title>
<authors>Jonas Rembratt</authors>
<owners>Jonas Rembratt</owners>
<requireLicenseAcceptance>false</requireLicenseAcceptance>
<description>bla bla</description>
<summary></summary>
<releaseNotes></releaseNotes>
<copyright></copyright>
<language></language>
<dependencies>
<group targetFramework=".NETStandard2.0">
<dependency id="Xamarin.Forms" version="3.1.0.697729" />
<dependency id="System.ValueTuple" version="4.5.0" />
</group>
</dependencies>
</metadata>
</package>

Answer 1

Ok, here's the latest outcome from my experiments with NuGet/VS4M/VS2017. One problem seemed to be that VS4M included 113 libs in the NuGet package so I wanted to see if that was the problem or not. I first tried to simply renamed the .nupkg file into .nupkg.zip on the Mac, then unpack it, then remove the .nupkg, then remove the 113 libs in lib/netstandard20 leaving only my own dll in there. I then simply compressed the folder again into "MobileApps.Auth.nupkg.zip" but it seems Finder won't take kindly to then simply removing the ".zip" suffix. So, I simply moved the .zip over to Windows and removed the ".zip" suffix there before moving it back to MacOS. In the end I'm left with a .nupkg that in essence looks just like the one I generated with VS2017 (see OP), that is a package that contains only my own .dll file.
This works.
So, the problem now is that:
This leaves me with having to go through a tedious process of manually removing all unecessary .dll files from my NuGet package whenever I re-generate it. Is there really no way to configure the 'nuget' build to exclude these libs in the first place, like VS2017 does?
Why didn't it work when I built the .nupkg file on VS2017 and then tried to use it with my projects in VS4M?