Do you… Do you think that the water in the bowl is what gets sprayed on your ass?

Is this like a mental locational thing? There is no way the unsanitary water from the toilet bowl can back feed into the water line. They are isolated mechanically via the tank float and by gravity because water can’t travel back up into the tank from the bowl. The bidet and toilet fill valve is piped into the same water line the hand sink is you use to rinse your mouth after brushing your teeth.