I've never used a pre wax cleaner, seems a bit pointless really!
What I've done once or twice a year when waxing and/or claying is this:
1: Wash with shampoo of your choice, you can snowfoam it all up before washing if you wish, it might loosen off surface dirt, it might not, it just looks cool and funky if anything tbh...
2: Rinse, no need to dry, the panels should be still wet before claying anyway so save yourself some energy.
3: Clay with a spray detailer. Doesn't have to be anything fancy, just something to keep the panels lubed up while the clay is going over them. Only clay once you start to feel surface bumps when you run your hands along the panels after a wash. if it's smooth, you don't need to clay.
4: Polish, SRP is good as it will mask any light scratches and swirls.
6: Wax such as 476s. This will protect the SRP from weathering away so quickly and in my experience it has lasted up to a full year down here.
You do want to wax after buffing off the polish, you want that layer of polish fresh and not contaminated with dust and dirt.
Different people do it differently, this is how I do it though and most have seen my car so you know the kind of results that can be had with the above
One dollop hit the drivers window and ran all the way down the door