Is Alex Garland a lackluster director?

I wasn't a big fan of Ex Machina, I went in expecting too much and it just wasn't for me, but something that really bothered me was the acting. It seemed too stiff, aphatetic, as if they were tired or reading direct from a script. Of course there were moments when emotions showed, but they were brief and well, lacking. The "fight" scene was a bit awkward too, and I couldn't put my finger on why exactly until I watched Annihilation.

Here the problem with the stiff acting happens again. I brushed it aside as a first timer mistake in Ex Machina, but in his second movie, and with a larger cast, the problem persists, and it shows. I could kinda get it in the first movie, since the characters weren't really the relevant part of it, but Annihilation is way more character driven, so the fact that those very human personalities were put into actors who looked like walking potato sacks felt awkward thoroughly. While it might be intentional (the most emotional of the bunch was the junkie, for obvious reasons), I wonder if it was a good idea. At the beginning where Portman is at class it looks more like an student making a presentation while reading off a paper than a teacher.

And yeah, the reason I found the fight scene in Ex Machina awkward shows in Annihilation with that last scene. This seems to be an unpopular opinion among fans of the movie (yeah, I liked it, don't get me wrong) but that scene didn't really do anything for me. The whole concept was impressive, but the conceptual dancing plus the lack of emotions of the scene made it uninteresting and, well, boring to watch.

And I mean, I don't have any problem with slow scenes attempting to create some kind of, uh, visual poetry. I like Tarkovsky, Werckmeister Harmonies is one of my favourite movies, but I think Garland just don't have it in him to control these kind of scenes.