Real-time background blur depends on a clear view of the subject. A few physical setup choices can improve the result more than pushing the effect to its maximum setting.
Create separation before adding blur
Stand away from the background and avoid colors or patterns that closely match clothing or hair. Keep the camera steady and frame the full outline of the subject.
Light the face and edges
Use soft light from the front or side and avoid a bright window directly behind the subject. Better edge contrast helps the camera distinguish the person from the scene.
Test at the final resolution
Choose a moderate blur or backdrop, record a short clip, and review movement around hair, hands, and objects. Confirm audio, orientation, storage, and framing before recording the full take.