My last Challenger was Pitch Black. I taught myself how to do paint correction on it. I sealed the car once a year with Collinite #476 and periodically topped that with Jescar Paint Refresh.
Two fundamental requirements for keeping any car clean; quality products and a solid hydrophobic foundation.
Products
1. Quality towels/mitts of differing types for different jobs. It doesn’t matter how much time or money you could nvest in your paint; if you don’t buy quality towels, you’re going to mess it up.
Mitts: I’ve found that the green knobby mitts from AutoZone are as good if not better than anything else
Non-waffle weave Microfiber: study the chart below, especially the part bordered in red; learn it, live it.
For drying, until recently, I was a huge proponent of The Rag Company’s “Platinum Pluffle” towels for drying...but I’ve found something even better: Gyeon’s Silk Dryer. It is far more absorbent than the Pluffle, and on a properly prepared paint, simply glides across absorbing everything.
You need quality products like those above to maintain your paint, but even they won’t work as designed if the paint isn’t made hydrophobic. You can do as I did on my old car (sealant, with a topper), or you can use a coating, but these won’t work if you don’t clay and polish your paint first.