Well, while the first handful of episodes of B5 weren’t nearly as strong as the episodes of the 2nd or 3rd season, I still thought they were pretty good, and definitely left me looking forward to the rest of the show, which is more than you can say about the first three episodes of STD.
But let’s leave B5 out of it since we disagree, and try to compare the first three episodes of STD with the first three episodes of The Expanse. By episode 3, we’ve already been introduced to most of the major characters. We know Errinwright is probably a bad guy, can cheer for Avasarala and Miller, and we’re on the edge of the seat watching Holden and his crew go from bad, to worse to “holy shit!” These are characters you can love and hate, sympathize with and cheer for. We know where the story is going and got two mysteries to explore (Julie Mao and the Cant).
Compare that with the first three episodes of STD. Any interesting characters? Aside from Lorca there’s zilch. Do we really care about the Klingon war? Eh, not really. There’s the shroom drive if you can get past the initial silliness of the idea, but even that is just the means to an end, rather than an interesting plot arc.