Filming matters more than anything else. Stand your phone side-on to the mat, far enough back that your whole body and the bowl stay in frame from stance to follow-through. Most disappointing results come from framing, not from the app.
Usually part of the body left the frame, or the clip is too dark or too shaky. Re-film side-on with the whole body in shot.
Tips are generated from the joint angles the app can actually see. If it can only see part of the delivery, the feedback gets vaguer. Framing again.
iOS Settings → Lawn Bowls Coach AI → enable Camera. The app can't record without it.
They stay on your phone. The app analyses them on the device and uploads nothing by default. Full detail in the privacy policy.
Email [email protected] with your iPhone model and what happened. If a particular clip fails, saying what you could see in frame helps most.