Its even more complicated now. USB4 has a lot of timing related things that the system has to do before you can even start sending data. More complicated, much of it is done in hardware, which might be nice for quickly slapping USB capabilities, buttttt is a bear if you're trying to build something thats not a computer. Theres cases where the device wont even power on unless you do everything just right hardware side. Gone are the days of simple signals and connections.

USB isnt so universal anymore