Agree with your point that Trump inherited a good trend created by Obama, that there is a lag to be accounted for, and that it would likely be better to look at periods of single party control.

For example, we had single party control under FDR, LBJ, and the first two years of the Obama administration, and those presidents are rightly associated with significant economic growth.

Clinton, on the other hand, may have benefited from the fact that his administration coincided with the information revolution and the productivity gains that came with it.