I would stop everything you are doing and let the tank settle. It should not take this long. When nitrites hit zero out do a WC.
The best way I have seen in 40 years to cycle a take is using live rock, if you are using dead rook then add a small piece of live rock or a little tank water from another tank with a small piece of shrimp to jump start the nitrate process. It is amazing how fast bacteria can multiply. Anything else is snake oil in my book.
Years ago we used pee in tank, then years later we used a sacrificial fish to start a tank.