Pictures like this are puzzling because they appear static. The reality is that everything is orbiting Saturn from left to right. Particles at the top of the picture are moving a little faster, those near the bottom are moving a little slower. Particles above the gap are overtaking Daphnis, and particles near the bottom are being overtaken. But the relative velocities are very small, meters per second or less. So the waves aren't bouncing up and down quickly. Instead, particles at the wave crest have been disturbed into an orbit with its peri-saturn a few km closer, out of a radius of 136,500 km.
The page https://spacemath.gsfc.nasa.gov/weekly/10Page28.pdf
gives the velocity of a ring particle as 29.4/R^1/2 where R is in Saturn Radii. Unfortunately, some of the other results on the page don't check out. But if the velocity formula is correct, Daphnis is doing 19.5 km/sec and a particle 1 km further out is going 7 cm/sec slower. It will take Daphnis many years to lap the particles on the edges of the gap. But it only takes Daphnis and the ring particles a couple of days to orbit Saturn, so the disturbed ring particles have plenty of time to trace out their new orbits and form the waves.
Short story: Everything in the picture is moving around Saturn at about 20 km/sec, taking just a couple of says to orbit. But, the relative velocities of everything within the picture are extremely small.
I'd love to see a close-up of the rings, too, but matching the ring planes is out of the question and an inclined flyby would have to have pictures timed to the millisecond. The end of the mission calls for some dives between Saturn and the innermost ring, so that will be our best hope.