How to enable intellisense for C# in vscode on ubuntu when dotnet was installed with rtx

Question

I am not able to get intellisense for C# on vscode.

I used rtx-cli, which is basically like asdf, to install dotnet 7.0.306 on Ubuntu 22.04.2. I can run dotnet command on my terminal.

I enabled shims with rtx as well, so there is a $HOME/.local/share/rtx/shims in the path. which dotnet points to inside that directory.

In VSCode, I installed the recommended Microsoft C# extension. I also set the following 2 settings in my user level vscode config:

"dotnetAcquisitionExtension.existingDotnetPath": [
    "$HOME/.local/share/rtx/installs/dotnet/7.0.306/dotnet",
],
"dotnet.dotnetPath": "$HOME/.local/share/rtx/installs/dotnet/7.0.306",

Here is the output of dotnet --list-runtimes:

Microsoft.AspNetCore.App 7.0.9 [$HOME/.local/share/rtx/installs/dotnet/7.0.306/shared/Microsoft.AspNetCore.App]
Microsoft.NETCore.App 7.0.9 [$HOME/.local/share/rtx/installs/dotnet/7.0.306/shared/Microsoft.NETCore.App]

And here it is for dotnet --list-sdks:

7.0.306 [$HOME/.local/share/rtx/installs/dotnet/7.0.306/sdk]

I created the project with dotnet new console --framework net7.0 which gave me a folder with Program.cs, myapp.csproj, an obj directory. I also created a myapp.sln file with dotnet new sln.

When I open VSCode, I get the notification that .NET Core SDK cannot be located: A valid dotnet installation could not be found...

I am not able to get any auto complete or error squiggles in vscode when I edit the c# file.

NOTE: $HOME everywhere up above is a placeholder. I actually used the real absolute path.