Source Record lets you record any source in OBS Studio. This is a filter that
provides an individual record button for any source, allowing you to record
sources independently from the main output.
Enable snaps on Kubuntu and install Source Record (OBS plugin)
Snaps are applications packaged with all their dependencies to run on all popular Linux distributions from a single build. They update automatically and roll back gracefully.
Snaps are discoverable and installable from the Snap Store, an app store with an audience of millions.