For example, I moved my torrents folder from /Users/username/Documents/Torrents to /Users/username/Torrents. The Catalina restrictions apply to specific folders like Documents, Downloads and Desktop, so Deluge works fine if you point it at a folder outside these locations. Until then there are a couple of workarounds that don't require granting it full disk access (which is a Bad Idea).
I'm not a developer, but going by this thread Deluge will need to be updated to work with the Catalina security changes.
