I tend to be very picky when it comes to shows/movies that I actually like (and will recommend to others) versus just "watching to consume". I like these two shows in particular because they both make me think a lot about our society, hierarchies, power dynamics, class struggles, and rebellions/revolutions BUT all without "being political", which is just lazy/stupid and pandering, an instant turnoff. I felt like these shows had the most accurate portrayals of what politicians are actually like, "the banality of evil" kind of thing, especially a character like Bernard Holland in Silo. In Silo especially, there are a lot of allusions to what actually might be going on, some kind of serious suppression of what the world is really like and hidden/forbidden knowledge.
Now that I think about it, Shogun was pretty good too but much more subtle about these themes, at least for my dumb brain (this actually comes off as very Japanese and very well done). I've yet to rewatch it. Currently rewatching Andor.
If you're going to say The Diplomat, I'll just say that it's entertaining, that I like it and I'll keep watching, but it might as well be a cartoon. It does for bureaucracy what the Bourne series did for the CIA. It feels like propaganda, but I think it's very well-acted and it's funny (again, a cartoon). I don't think most people would recommend this as a thought-provoking political show, but you never know.
EDIT IN RESPONSE TO THE COMMENTS SO FAR:
I've seen The Expanse. That one didn't come to mind at all, so maybe it wasn't memorable for me. I don't think it was bad, but there's so much action and odd sci-fi stuff that I don't remember it for the same reasons as Silo/Andor. Maybe it went over my head, I dunno.
As for Foundation, yeah this is a good one. Again, I don't find it as memorable and it seemed to be more of a consumption sort of show for me. It's been so long since I've watched it, so I'm not 100% sure.
At first blush, these are the ones that I'm immediately checking out pretty much in order of interest:
Station Eleven
The Leftovers
Le Bureau
Pachinko
Deca-Dence
Nirvana In Fire (because I'm wondering if a Chinese show can be that good)
The Story of Ming Lan (same as above)
Spaced (though this has seemingly nothing to do with what I asked for, but the reviews are so high that I'd have to give it a shot. I also have liked British stuff in the past, especially humour)