I am not sure if that could help you but you could try with the jamba framework GitHub - pongasoft/jamba: A lightweight VST2/3 framework
You can quickly generate an empty/blank plugin (one command).
Then with one command you configure the build
Then with one command you build the audio unit plugin
You can then examine what you get.
I am not saying use jamba for your plugins (although you are more than welcome to), but it would be a quick way to get a fully functional audio unit plugin built with the vst sdk…
Yan