Okay, so, in this case, because we have no idea which herald, we have to assume the worst, i.e. Taln, but coherent. In this case, it’s a matter of somehow getting around the supernatural reflexes. Taln has caught darts, while not even being aware of what was happening. Nale has shown that Heralds can move at supernatural speeds. Therefore, he could keep up with either a steel runner, or a slider. As for sheer power, he single-handedly took down so many fused. So going by numbers we literally cannot. A Herald using the full extent of their powers can easily escape or defeat anything we throw at them by drawing on Roshar. We literally cannot beat a Herald at full strength, we’d have to convince the herald to let us kill them. And so, since the prompt says they have a goal, that’s not likely. Which means force, something that cannot happen on Roshar without extensive casualties and investiture.
Therefore, the only way I see to kill a herald, without throwing a desolations worth of force at them, is to not fight them on Roshar. Kalak was unable to escape Felt, despite still being in Roshar’s shadesmar, which suggests that their powers rely on being in the physical realm on Roshar. Much like Sel. Nale would’ve been beaten by Kaladin if he hadn’t had those powers. As such, it is possible, while finding a person able to kill Taln in a fight of pure skill would be hard, it’s a lot easier to throw bodies at him here rather than on Roshar. In other words, it’s up to how many resources our Ghostblood has access to, and if they have any people with even a fraction of Kaladin’s fighting prowess, and whether they can get them to throw themselves against Taln.