Even I'll admit that Grid is complicated. It serves a valid use-case, but it's honestly a very rare one in my experience and the learning curve is steep

Grid is nice but overused in my opinion. However, at the end of the day whatever gets the job done and is sane is a valid solution in my eyes but I prefer to think of grid as anything requiring centering on two-axis and/or macroscopic to the task at hand.

So for instance I would do the responsive page layout in grid, probably. Then I would do positioning the elements within a article or section with flexbox.