Well, I'm going to give my personal opinion, and i hope nobody gets offended.
I believe that this forum should not deal with anything related to Retropie, which already has its own forum...
I don't go to the Retropie forum to ask questions about Attract-Mode, it would be a mistake for me to do so. Retropie is not designed to use Attract-Mode. They have forced it, and they have not been very well. They do not install Attract-Mode in a normal way, but as if it were another EmulationStation... Using unnecessary files and changing things and using many symbolic links...
Coming to this forum to discuss Retropie issues is like taking a Mercedes car to which everything has been changed, engine, sheet metal, paint, tires, aesthetics... that is, except the plate that puts Mercedes, to the official service of Mercedes.
Using Attract-Mode with Rasbian and RetroArch on a Raspberry pi works much better and faster than under Retropie. I have checked it personally.