I need help

I want to make a datapack where when you kill the warden you get a custom piece of diamond armor low chance I got the drop to work and I want that when a player gets a custom diamond armor piece e.g.diamond helmet it cant drop anymore from the warden I have no coding expreiance and use chat gpt. The warden drops the armor after 4th kill I have  a set when I kill it the 5th time I want that I only get sculk catylist going forth but I get armor duplicates can someone dm to help I can send you my datapack folder.