I finally finished Devs.
It took me 7 attempts to get through the final episode, because it just knocks me out, seriously, best sedative ever. Between the music and the monotone speaking barely above a whisper, and me not caring about the plot very much, I've never fallen asleep so easily in my life.
The ending was kind of like "uh...okay...sure?"
In the end, I was far more invested in the Russian spy plot than the reality-sim-multiverse plot, and I really enjoyed Kenton as a character, so I liked the whole Russian spy surprise near the end. That's was a great detail.
Overall, I would say the show had really great details. I had less than zero interest in the main plot or the main characters, but I would watch the hell out of a show that was a Russian spy thriller featuring all of the secondary characters.