The WSL 2 docker-desktop-data vm disk image would normally reside in: %USERPROFILE%\AppData\Local\Docker\wsl\data\ext4.vhdx
Follow the following to relocate it to other drive/directory, with all existing docker data preserved (tested against Docker Desktop 4.21.1)
First, shut down your docker desktop by right click on the Docker Desktop icon and select Quit Docker Desktop
Then, open your command prompt:
wsl --list -v