FWIW .......
I agree with the comments above. The only bit which does anything is what is in contact with the vehicle/dirt, the foamy bubbles are just for show.
After reading stuff many years ago I switched from using any sort of sponge to a soft brush. Sponges have a very high risk of scratching the paint with dirt.
I picked up a "MucOff" brush which is very good, a soft bristle in a rubber body so fairly paintwork safe. Recommended. Mine is the predecessor of this, haven't seen the new one
https://www.sportsbikeshop.co.uk/mot...nt_prod/102003
I've been using Autoglym products for years, other good stuff is available. Usually get the bodywork shampoo in 2.5L for cost effectiveness, ebay/amazon etc. or even Halfrauds isn't much more expensive. There may well be fake stuff about so probably worth paying a couple of quid extra for certainty it's genuine.