The amazon foam cannon is what I use and works great years later. You’re going to want to clay bar the car after washing it thoroughly. The clay will pick up the stubborn contaminants that get stuck in the paint.
Just make sure you seal or wax it right after that, as the surface will be bare.
My usual workflow:
Wheels
Powerwash to get any heavy debris off (SunJoe SPX3001 with MTM PF22 foam cannon with smaller orifice)
Strip wash (Purple power)
Decontaminate with iron remover (Bilt Hamber or Iron X)
Powerwash
Claybar (Mequiar's pro medium, I think that's the blue one)
IPA wipe down (CarPro Eraser)
Polish (Sonax polishes and Lake Country CCS pads)
Sealant (Been trying Turtle Wax Seal N Shine)
Wax (Been trying Chemical Guys Hydroslick Wax, really not impressed with durability)