Here is a nice instruction how to migrate wsl to another drive.
A couple of nuances:
- When you export the image there is no need to define the version of WSL. But for the import you should do it (if you use version 2 for example), by using the version parameter, otherwise, you will get a confusing error about an incorrect parameter.
- To define the default user you should use the command that may vary depending on the os version. For example, for Ubuntu 20.04 the command looks like ubuntu 2004, not ubuntu.