I don’t understand why you need to use chemicals for standard driveway/patio cleaning?
I’ve never needed to use them, a turbo nozzle works great, and Untill recent times, was the only way people cleaned hard surfaces.
I also run a softwash business separate to my window cleaning, so have plenty of experience with it, even then, I can’t think of any reason to use it and faff about with it on driveways/patios.
For me, softwashing is for render/cladding and the like. And a completely different job.
For example tomorrow I am softwashing a tennis club pavilion, I am also pressure washing their path and patio. Two separate jobs, no needs what so ever to even think of softwashing the path and patio, there just isn’t a need, it’s a waste of chemical and time.
Now obviously if you have very stubborn marks, then yeah, but I can count on one hand he many times I’ve used Chems on a hard surface. Pressure washing works just great!