Use this permalink from https://learn.microsoft.com/en-us/aspnet/core/host-and-deploy/iis/hosting-bundle?view=aspnetcore-9.0#install-the-net-core-hosting-bundle
The bundle file is called something along the lines of dotnet-hosting-<VER>-win.exe
Create new Application Pool with "No Managed Code"
Publish the application with the following options:
Release, Net9, Self-Contained, win-x64 and NOT a single file
Mark the folder as application in inetmgr.exe
Set its application pool to the newly created application-pool
(.net core apps must have 1 application pool per application)
Check the site in inetmgr.exe and add https bindings if necessary
Test if it works