Part of macOS
rapportdNearby devices
○ Leave it
Lets your Apple devices find and talk to each other.
What it is
Used by Continuity features such as Universal Control and Sidecar.
If you stop it
macOS starts it again straight away. Leave it.
The verdict
○ Leave it. Part of macOS, or something that starts again by itself. You never need to close these.
In Activity Monitor
rapportd
From Procession’s guide, in the words the app shows.