yes, Rad Power bikes are made in China.
It is very similar to BAM Power and DJ eBikes I believe they all come from the same factory.
I think Jiangsu Kuake builds Rad Power bikes but I'm not sure.
I know Juiced Bikes are built by Luyuan Bikes.
Most bikes from USA companies are made in China, by Chinese company/factory. USA companies typically do not have their own factory.
They're all imported from China and re-branded.
I know this because USA ebike companies do not hide this fact at all, in fact, they are quite upfront about it.. when you look at their YouTube channel, they even show you the tour of Chinese factory.