worldedit bugging out?

idk what i'm doing wrong, fired up a new Spigot server and downloaded the latest version of WorldEdit, but when I go to do much of anything using it, I keep getting errors saying it's unsupported, despite using the latest Spigot version. Console begets errors complaining about another plugin called Paper, but I don't have any plugins that would conceivably conflict with worldedit installed, nor do I recall WorldEdit ever having any dependencies.

is the latest version of WorldEdit just broken, or am I missing any dependencies I didn't think about? I feel like an idiot even having to ask given I've done this plenty of times in the past without incident.