MemberJuly 19, 2023 at 1:58 pm
Very difficult to answer. It can be different issues, unique, or a combination of many.
For example, distance between subject and camera, non-coverage of focus points, unsteady hand, low light, too fast clicking without focus, too shallow depth of field, incorrect shutter speed, unbalanced exposure triangle parameters, choice of focus points, etc.
However, I can say with certainty that there is no problem with your camera or lens. Unless there is some manufacturing defect in that particular piece (improbable)
I suggest you do the courses diligently and you can fix your problem.