Ozark has flaws for sure. Darlene Snell and Ruth Langmore both seem to have inconsistent motives depending on what is plot convenient at the time.
Bipolar Ben from S3, on the other hand, was an absolutely magnificent arc; pitch perfect all round, story, character, acting.
That whole season was so desperately tragic, and Laura Linney, Tom Pelphrey and Julia Garner were superb.
Ozark went downhill a bit after that, I think that it just couldn’t follow that, didn’t have any character arcs left to develop, so compensated by messing badly with the ones it had already established, and filling the rest with identikit ‘cartel stuff’.
Bateman was the weaker link throughout, I thought. He’s basically a blank canvas for other characters to bounce off.
There aren’t many of the so-called ‘classic’ series that maintained the quality past about season 4.