The photos aren't very good, sorry. I'm not asking for you to confirm is it genuine but only if, in your opinion, it might be.
I think the bottom and colors look right. I also think this dragon design could be of kangxi period.
This is not antique but a modern item. Basically this decoration appears on Chinese style plates, which have a different rim shape. This is a western style plate with a shape as was used for export. The foot rim seems to be rounded, which is incongruent.
And why should it be Kangxi?
From what I've seen, the outer rim is also too decorated for a Kangxi period export.
There is nothing specifically Kangxi here. This decoration is called "dragon over the wall" in Chinese and appears mainly in the mid-Qing dynasty on Chinese shaped dishes, plates, bowls and cups, although it may have also existed earlier and later.
Chinese shaped plates are bent up only, near the outer edge, with a larger flat central area than the western one. That makes it ideal for such decorations. I would be interested to see any such decoration that is old and appears on western plate shape.
This dragon is not Kangxi.
The owner told me kangxi. You are right about the the foot rim, I should have known better.
You can also tell from the tip of the dragon's tail that it is not Kangxi.