guys. if you have zero compression in cylinder 7, you are having burnt valve that is warped and not seating on the valve seat. there's no point in doing anymore checks, OP already took over valve cover and the keepers/springs seem to be undamaged and that was the only check needed. while other member's posts are coming from a good place, it's really all a waste of time after the compression was determined as zero and then checking physically valve gear from the top after removing the cylinder cover.
Replace the engine head with a good used unit, or remove and send damaged head for repairs.

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2003 4.6, esotril blue, over 215,000KM. Every previous owner failed to keep up the vehicle maintenance. Restoration project.