Weather is the enemy
Suede in a February commute is a choice. Leather after a wet night bus is a habit. Neither is solved by a magic spray you saw in a reel.
Wipe with a barely damp cloth the day the dirt happens, not the next weekend. A dedicated sneaker cleaner (Jason Markk, Reshoevn8r, Crep Protect cleaner — all easy to buy in the UK) beats washing-up liquid, which dries the finish. Stuff the toe with paper while it dries, away from a radiator. Heat cooks glue.
White leather yellows if you leave it wet in the sun. Dry it in a room, then use a white-specific cleaner on the foxing, not on the suede overlays.
A suede brush is not optional in this country. Brush when dry, always. Water stains on untreated suede are mostly forever; a protector spray before the first wear is the only prevention that works. If they do get soaked, let them dry slowly and brush the nap back. Do not put them on the boiler.
Salt marks from winter pavements: a specialist suede eraser, then brush. Repeat. There is no one-wipe miracle.
Knit uppers hold water and smell if you bag them wet. Dry them stuffed, in moving air. A machine wash is how you separate a midsole from an upper. Boost and similar foams can be wiped; they do not need a bath. If the sockliner stinks, pull it out, wash that, leave the shoe alone.