I had a similiar issue and noticed that I needed the following to be true:

1. Although I had installed WSL, I was missing an important individual component, make sure within the Visual Studio installer that you have installed the "C++ CMake tools for Linux" (in addition to the "Linux and embedded development with C++" workload)

2. Have WSL installed and set it up as a Remote Connection within visual studio. To do this follow the instructions on this page

• Hostname: localhost OR the IP address of wsl, this can be found using the following command in PowerShell/Command Prompt

wsl hostname -I

• Username and Password --> the same as your WSL login details
• Port: 22