No it’s pretty straightforward. The game fully supports the total number of engines (was it 16?), you can control them individually from the virtual cockpit, I presume the plane simulation gets all of the data, etc. They just did not add axis and keybindings for them because this would have added hundreds of items to the keybind setup screen. They plan to add them later but only after redesigning the keybinding handling.
Obviously this sucks for anyone flying the AN225 with 6 hardware throttles, but that is likely a very small percentage of players, meanwhile I must admit I’m glad they didn’t add hundreds more entries to the keybinding setup screen.