>>106636206
I'd say it depends on the design of the spray tube. Decent bidets should have something like pic related where the actual sprayer isn't exposed unless you pass the "self-cleaning" threshold on the pressure dial. I think some super fancy bidets even have features that move the sprayer out of the way entirely
That being said, if you have some kind of explosive diarrhea that shotgun blasts poop all over the bowl, yet, chances are that you're gonna get the sprayer dirty. Make sure you're fully cleaning your bidet when you're regularly cleaning your toilet.