Urine Smell From Half Bath Toilet

Few thoughts. Make sure the black water tank vent pipe is operating correctly, dump some bleach and soap in the black water tank and drive around/dump, check/replace the air vent under the bathroom sink (many bathroom sinks are plumbed to the black water tank)- they only cost about $10.

Washed the cover and seat.

Did you wash the inside of the lid where you peed on it.

Some of these toilets have a plastic water dispenser which points the water to the side of the toilet..it is a small plastic piece and perhaps this plastic water distributor needs to be replaced.

The toilet holds water. No leakage here that is why I am stumped.

If the toilet does not hold water for an hour or so, I would guess that you have a leaky gasket.
They do have those toilet bowl deodorant blocks that hang on the edge of your bowl until you find the source.