What happens today if I pick up any random USB-C and try to charge my non-Apple phone is that it charges, in some cases fast, in others slow. I don't have to carry around a special cable. I would expect the same from Apple, once they implement it.
As for the data stuff, I'm sure they will manage somehow.
Try your definition of “slow” on a iPhone 12 Pro Max using a cord that only delivers power over 5W. Better yet, try charging an iPad 12” Pro (that does have a USB C port) with a USB C cable that can only do 5W. Now try to use that same “standard USB C” cable to charge a 16 inch MacBook Pro.
Of course that standard cable is not guaranteed to support data at all.
