Interesting crosstabs, the poll has Trump even in approval, but the poll has 48% Republicans. After looking at the crosstabs, its clear that the poll is rather R friendly, but it does seem that two things are true.
1. Ducey is experiencing a bounce due to McCain
2. Sinema is likely going to stay stagnent, or lose some of her lead
How does 2. follow from the point you made about the sample being too R-heavy
Its due to the fact that Sinema is leading at 47
with the current sample. And a good portion shes winning are Republicans. Im pretty sure the Rs left in the sample will go against her, which will decrease her lead, but they may go to Sinema simply for the same reason the others did. Overall, I know that Sinema isnt going to be expanding her lead