Have a Optiplex 990 I have have successfully got macOS Sierra running on. It has a Realtek ALC269 Audio chip on the board, and Im not sure how to get it working. You guys were amazingly helpful in getting my Touchpad and Audio working on my 6430, so I am posting in hopes that you guys will have a fix for this as well.
Please let me know what information would be useful.
I have attached my config.plist and captures of the Kexts in EFI and the 2 added to S/L/E
Opti990.zip