[okanat]

You need to enable sparse VHD! However it doesn't alwyas trigger. I have moderate success with enabling TRIM systemd service on the distro.

Here is the tracking issue:

https://github.com/microsoft/WSL/issues/12103

And if nothing works you can still manually optimize.

https://superuser.com/questions/1827953/reclaim-wsl2-disk-sp...