I have three chargers.... but lately it's been getting weird. I have a 2017 iMac too. Used to be, I'd plug my iphone into the white macintosh jack and it'd charge. than it was plug it into that one, and quickly plug it into the black macintosh cable. I'm currently resorting to turning the phone off, and then plugging it in... it's completely compatible I'm fighting some bug or starting to believe mac is sabotaging their own gear but this will be my last apple products trust me.
Wireless chargers just keep you from having to plug the thing in. So you can just lay it on top of the charger. Its not sending wireless signals out or anything.