I like Rings of Power, currently the best live action fantasy show on TV. The Expanse, I didn't get past the first episode. I think the problem was I just didn't care about any of the characters.
I mean, that first statement is a very bold position, which "currently on" and "live action" seeming to do an inordinate amount of work! I think it's fair to say that very few people indeed had a high opinion of S2, whether serious fantasy fans or casual viewers.
The Expanse is an interesting one because it's horribly badly acted and we have to pretend it isn't. I got a death threat once for saying that, note, but I'm sorry my nerds, the acting... it is bad... real bad. Like Stargate Atlantis bad. Also, none of the starting characters are like, inherently charming. They're all kind of jerks of various kinds.
That really puts a huge damper on caring about the characters initially.
If you stick with it through this terrible acting, mediocre-but-not-completely-awful writing, various par-for-the-course/table-stakes apologia for fascism (sorry but the show and books are initially way too kind of the fascists on Earth and Mars and even a little too kind to the psychos in the Belt), the somewhat ludicrous plot, and only okay SFX, the show slowly, steadily, becomes kind of good somehow.
The characters, despite being jerks, also mostly grow on you (especially everyone's favourite neurodiverse psychopath Amos - he's a psychopath in the nicest possible way, to be clear, and I totally get his deal). Also eventually a lot (but not all) of the fascist apologia gets dialled back or undermined or shown to be part of the problem that might destroy the inner Solar System (including Earth), not "cool badassery". And the story becomes gradually more interesting. That lasts for like what, four seasons?
Then in S5 or S6 (I think S6 mostly) it goes steeply back downhill because we get some really terrible overacting from actors who
I know can do better because I've seen them in other stuff (which means it's on director for telling them to act like that), and just really a ton of melodrama.
It's also continually held back because the male lead can't act/won't act or has a really bizarre idea of what his character is supposed to be. The character is bad enough in the books but much worse in the TV show. I had to just tolerate him.
Also for some reason the showrunners love, love, love to cast absolute master-tier super-actors like David Strathairn and then put them in scenes with like, novice actors or really bad actors, and... it's a mess. Again the directors do seem to egg their better actors into a lot of scenery chewing and overacting which I guess levels things out a bit.
(It's not like it's unique in this - there are quite a number of successful police procedurals that adopt this approach to acting. But it's weird as hell to see it outside one of those.)