Yes, sorry, I mean it's a race with 3rd party displays. Studios work because they are "always on". There is no race, once laptop wakes up or connects displays are already there. I think the handshake always "stays alive" and macOS just disables the connection, but it's always there.
To see what i mean hook up a studio display, and an external monitor. The studio will come up instantly, the other display will take anywhere from 3-10 seconds. When you have nothing but 3rd party displays, the order they wake up cannot be guaranteed. With studio displays, there is no delay, so there is no race, thus always in the same order.
I have a suspicion (purely my opinion and guess), is that the reason studios run ios is for this exact reason. A 5k monitor handshake, and register with macOS takes a very long time. To avoid that, apple decided to just have the chip always carry the signal, even when not hooked up. When you plug in a studio, macOS sees it as already connected and just pushes the stream. Just my guess based on what I've seen.
What I'm getting at, is if the above guess / theory is true, then there really isn't a fix without changing how displays are detected. And if that's the case, apple decided it's easier to just add another chip to their displays to avoid that issue altogether.
