I don't ride my road bike or our road tandem through more than an inch of water. But I've been caught in the rain several times with no ill effect.
Now, my mountain bike, my bikepacking bike and our mountain tandems are another animal all together. It hearkens back to my TD ITT back in 2017. I hit a stretch of road torn up by logging trucks and graded to keep the locals happy. If one wasn't careful, you could hit really sticky mud that would seize wheels and get gravel and sand in your drive train that makes it impossible to pedal. A couple of miles down the road, I found a raging mountain stream and was dunking as much of the drive train as possible to get the mud off of it. Never had any ill effects afterwards.