@Biswapriyo Okay. So I tried it now with a self-made .tar.gz from Fedora's ISO and with the alpine .tar.gz you mentioned in your answer. Syntax as provided, folder named "Fedora"/"Alpine", nothing in it except the .tar.gz and WslInstall.exe. Fedora promisingly starts, but then throws Error: 0x80070057, while Alpine does not even start and immediately throws Error: 0x8007007b. Tried PowerShell as well as cmd - no difference. WSL is active. I'm investigating...

The procedure for making Fedora tar.gz is little different. But the alpine.tar.gz will work from direct downloading.