To hear that there’s an overarching plot bumps it up a few notches.

Even better. It's an overarching plot that progresses without the protagonist. Too often, side characters seem to stop existing the moment the main character's gaze is pointed somewhere else. Like a NPC in a bad video game. In Silent Witch, the overarching plot is progressing without any MC input, and she is just made aware of it in hindsight. Things happening behind the scenes become clearer with each volume but they are not things that MC has any active role in. It's more like the actions MC takes are casting ripples, and those ripples have an effect on the big subplot. It's good and I want to see where this is going. MC is also getting a lot less annoying in the later volumes. I initially dropped the first volume because I hate timid characters, but I'm happy that I picked it up again. Definitely one of the better series.