Visual Studio Code – OmniSharp requires a complete install of Mono (including MSBuild)

OS: Ubuntu 22.04.1 LTS
OS Type: 64-bit
GNOME Version: 42.4
Unity Editor Version: 2021.3.13f1

Error:

OmniSharp requires a complete install of Mono (including MSBuild) to
provide languages services when `omnisharp.useModernNet` is disabled
in Settings. Please install the latest Mono and restart.

I am using the Unity Engine on Ubuntu and installed VS Code to develop my games.
Every time I try to open my project on VS Code, this message pops up:

Everything was fine and running correctly until I installed and ran LXDE for a better performance.
I switched back to GNOME and removed LXDE completely, still didn’t work.

My currently installed tools & extensions are:

• C# extension
• dotnet https://dotnet.microsoft.com/en-us/download/dotnet/sdk-for-vs-code
• mono https://www.mono-project.com/download/stable/
• msbuild https://launchpad.net/~eofla/+archive/ubuntu/msbuild

salah@salah-ub:~$ mono --version
Mono JIT compiler version 6.12.0.182 (tarball Tue Jun 14 22:35:00 UTC 2022)
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)
salah@salah-ub:~$ msbuild --version
Microsoft (R) Build Engine version 17.0.0 for Mono
Copyright (C) Microsoft Corporation. All rights reserved.

17.0.0.25701
salah@salah-ub:~$ dotnet --version
6.0.110

And my settings:

"omnisharp.path": "latest",
"omnisharp.useModernNet": false,
"omnisharp.monoPath": "/usr/bin/mono"