Reference assemblies for .NETFramework not found (4.7.1)

I've recently set-up Linux on my pc (Deepin, a distro based on Debian). In that fresh set-up distro, I installed VSCode and unity since I'd like to play around with game development. VSCode since I saw some warnings somewhere, I also went to install dot net from the official Microsoft website which seems to be an old version "3.1". But even though .net is installed, I still get the following error when starting VSCode:

The reference assemblies for .NETFramework,Version=v4.7.1 were not found. To resolve this, install the Developer Pack (SDK/Targeting Pack) for this framework version or retarget your application.

From a quick google, I found that installing mono should fix that error, but it apperently didn't. I tried rebooting, going thorugh the install process again, but the error stil appears. What am I doing wrong? Im new to game developing as well as working on linux, I just want to play around with that stuff. My mono -V:

Mono JIT compiler version 6.12.0.90 (tarball Fri Sep  4 14:03:37 UTC 2020)
Copyright (C) 2002-2014 Novell, Inc, Xamarin Inc and Contributors. www.mono-project.com
        TLS:           __thread
        SIGSEGV:       altstack
        Notifications: epoll
        Architecture:  amd64
        Disabled:      none
        Misc:          softdebug 
        Interpreter:   yes
        LLVM:          yes(610)
        Suspend:       hybrid
        GC:            sgen (concurrent by default)

My dotnet --info:

.NET Core SDK (reflecting any global.json):
 Version:   3.1.402
 Commit:    9b5de826fd

Runtime Environment:
 OS Name:     Deepin
 OS Version:  20
 OS Platform: Linux
 RID:         linux-x64
 Base Path:   /usr/share/dotnet/sdk/3.1.402/

Host (useful for support):
  Version: 3.1.8
  Commit:  9c1330dedd

.NET Core SDKs installed:
  3.1.402 [/usr/share/dotnet/sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.App 3.1.8 [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 3.1.8 [/usr/share/dotnet/shared/Microsoft.NETCore.App]

To install additional .NET Core runtimes or SDKs:
  https://aka.ms/dotnet-download