A commonly recommended option for this is the Manfrotto Magic Arm. It’s a heavier-duty articulating arm than the small monitor-style arms and is intended for photo/video support use.

Based on the community answer, it can handle roughly 6 lb, which is in the range of a 1.5kg camera-and-lens setup. It’s also designed to pair with clamps such as a Manfrotto Super Clamp or Quick Release Clamp, so it should be easier to mount securely to your horizontal bar.

For an overhead rig, stability and safety matter more than compact size. If you use a ball head, make sure the total load rating of the arm, clamp, and head all exceed your camera setup, and tighten everything carefully before suspending gear over a table or subject.