I don’t believe the leaders of these Christian nationalist movements are Christians as a rule, no. They are money makers.
I don’t know if it’s possible to successfully sway me from that, perhaps with cases?
However, I did not consider the followers. And as far as the followers of these movements go? Yes, they are likely quite genuine as believers are. The message can change but a believer is a believer in whatever the belief is.
My default position is to place leaders and followers in different classes.
So if a leader says [x]
it is not the same as when a follower says [x]
This is true for any hierarchical situation.