The trouble is that the soapy spray also does for beneficial insects and predators who will eat your aphids as well as bees which pollinate your plants.
I never spray anything in my garden but I do have plenty of bird feeders and find the birds will hoover up the insects to feed to their young. In time, ladybirds and hoverflies will come along and scoff aphids in their hundreds as well as caterpillars on brassicas.
If I do see a plant in trouble, I squish with my fingers or use the hose pipe to spray them off. until the predators arrive.
If you must spray with chemicals of any sort, do it late evening when it will have least effect on the good guys.