WSL on Windows Terminal Preview won't start
While we should work on troubleshooting your \\wsl$\ problems as a separate topic, my recommended way to launch into the home directory with a WSL profile in Windows Terminal is to use:
wsl ~ -d Ubuntu
The ~ must be the first flag after the wsl command.
Next up, see if \\wsl$\<distro> is available in File Explorer. It seems like there may be a problem with the shared drive.