I found a page that said that one needs to use the 'rdctl shell'-command and the add the /etc/docker/daemon.json' through that.
With an empty daemon.json it works but when I add:
{"hosts":["tcp0.0.0.02375"]}
Rancher Desktop don't start.
Last logentry
Running: wsl.exe -- distribution rancher-desktop --exec mkdir -p /mnt/wsl/rancher-desktop/run/data