Believe if or not… I just cleaned year old cat urine stain out of a carpet with Oxiclean laundry stain remover spray. It may work on the floor.
Just spray it wet with the spray and put a white towel over it and let it set for an hour or more that’s what I did to the carpet and the dark urine stain was completely gone, The carpet looked like new.
Try some white vinegar….dilute it if you would like, add a cup to a gallon of water…