I don’t know if it will solve your issue but avoid space and special character in the directory used by UE : C:\Users\Oğuzhan ATA => C:\Users\OguzhanATA …
see this post as an example of issue with UE 4.27 : UE 4.27 how to fix issues in visual studio code: "red squiggles" and "Unable to resolve configuration with compilerPath C:\Program"