vs2022 17.8 added .net 8 support which included new project templates that support .net 8. which project template are you using? not all have been updated to support .net 8.
to check the .net 8 templates have been added, create a new console app for windows, linux and macOs and see if .net 8 is available. if it is all is installed correctly.
you can force install template:
> devenv /installvstemplates