Thanks for your recommendations of
Line of Duty 
I will probably try it again later today. (Last time I started it, it seemed too complicated for what I wanted to watch at the time, so I gave up after about 2 episodes.)
But then, for complicated, I got drawn into a murder mystery called
Who Killed Sara?. It's on Netflix but is geo-blocked in Europe I think. Probably just as well as it's set in Mexico City and has the true-to-form excessive Latin American drama:
"OMG, you mean the cook's schizophrenic daughter is actually my sister?" Actually that sounds like a Dickensian plot twist, so you'd probably like it, TH
Does a 2-part documentary count as a TV show? If so, very interesting is the Netfix doc about The King,
Elvis. As Netflix docs tend to, there is no voice-over narration, instead the story is told by clipping interview comments together. Frankly I find that an irritating technique because (a) you have to listen to dull, unscripted people and (ii) it takes twice as long to work through the narrative. Of course, that is also Netfix's plan, I suspect: cut costs on script-writers and spin the program out as long as possible.
Nonetheless, for me, watching Elvis's story unfold for the first time, I found this documentary fascinating.