Actually, you can get them. I have factory Ford manuals that show all of the wiring diagrams, Harley Davidson manuals that show all wiring diagrams, Polaris factory manuals that show all wiring diagrams, etc. and these are all OEM manuals not aftermarket. It’s unfortunate that Dynamax doesn’t do the same.
Please confirm something: I have wiring diagrams for my 2001 Ford E350 as published by Ford. Huge manuals. But I can find nothing for a 2020 Ford Mustang of any model. I am told that Ford ceased to make this information available after 2010 although some after market manuals exist for sporadic models like the Focus but only through 2014. What I am hearing you say is that you can get current workshop manuals and wiring diagrams for current production vehicles?