Using Lines as Cutting Path?

https://preview.redd.it/tz0e5z5ty55h1.png?width=2905&format=png&auto=webp&s=9577cc99e6ef88d6abfac208fc061c469693e28a

Is there a way I can cut "along" this line rather than cutting a hole the shape of the closed geometry? I sketched this onto another part to draft the routing of an O-Ring channel. Is there a way I can use this as a centerline to cut a channel of my desired depth/width? Or is there a way I can "mirror" this same geometry 1mm inside/outide the current path to create a 2mm thick channel?