I thought this was going to be about how writing a whole book is hard.
But yes, this is also hard!
I will say, I tend not to be someone who overly fixates on my villains. I feel like some people get too close to justifying their villains. Bad guys are cool, I get it. But like you said, villains don't have to be smart or crafty. I think villains are more
interesting when they have a point but are simply going about it the wrong way. In
Totality, Cylence's primary motive is making the universe safe for Totality, which is not much different from what any other leader would do. It's just doing it with slavery and genocide is not great.

I never really think of him as sympathetic, just narrow-minded. Plus he has a clear cruel streak. Probably the most fun bit is learning about who he was
before he was Totality, though the details from that are mostly in the next book.
With
Sender Silent, Mark Titus is the nominal villain, and he's not really sympathetic
at all, he's just a big jealous jerk. But the co-protagonist is also a dickhead so, man, tough call there. Sometimes everybody sucks. My only hope at this point is making the Carpathian cool, but he's more weird than anything.