Now go enjoy those extra gigabytes… or reinstall WSL fresh with wsl --install . Your call.
Use this if you want to remove Ubuntu, Debian, or Kali, but still want to use WSL for other distros. wsl unistall
If you want to save your work, open your distro terminal and back up your files to an external drive or a Windows folder (accessible via /mnt/c/ inside Linux) before uninstalling. Now go enjoy those extra gigabytes… or reinstall