Localhost Loopback has now been officially added to the update 2308 of WSA, and so this guide is probably outdated now.
Preface: You want to connect WSA to the localhost (Windows 11 hosting machine) or to a development server I run on Windows 11 or any such scenario where you would want to connect to the Windows 11 localhost, but are unable to
1. Run PowerShell as administrator
2. Execute
Set-NetFirewallHyperVVMSetting -VMCreatorId '{9E288F02-CE00-4D9E-BE2B-14CE463B0298}' -LoopbackEnabled True
3.Execute
New-NetFirewallHyperVRule -DisplayName LoopbackAllow -VMCreatorId '{9E288F02-CE00-4D9E-BE2B-14CE463B0298}' -Direction Inbound -Action Allow -LocalPorts [PORT]
(replacing [PORT] with the port you're trying to expose)