I'm on Windows 11 x64 and VS 2022.I had exactly the same issue of missing MAUI APP project type.
First I had to rename (or you can delete it) the folder
C:\Program Files (x86)\dotnet
to C:\Program Files (x86)\_dotnet
as it was causing a conflict. Also I added C:\Program Files\dotnet
to my PATH environment variables, restarted the PC, then I was successfully execute the below command to install the MAUI templates.
dotnet new -i Microsoft.Maui.Templates