The "no high idle on cold start" issue is all over MUD threads. I have it too. I chased down issues over the years. I had a VAF issue but actually it was benign. I have cleaned injectors and installed new connectors. I have OE new fuel pressure regulator and IAC. both temp sensors are new. Etc.
Mine is also a bit loppy when clod, smooth when warm. I even spent diagnostic time with Jackson and his fancy OBDI OEM code and other stuff reader.
Corbet's solution is good "I've kind of just accepted it"