Pollen is abrasive and acidic
Those grains are hard, irregular, and slightly acidic once wet. Wiping a dry dusty car with a towel is essentially dry-sanding it, and letting the dust sit through a spring rain starts a mild acid etch.
The plan
Touchless rinse two or three times a week during the peak — never a dry wipe. Keep a sealant on the paint so the pollen has less to key into. Run the presoak long enough to float the grains off before any pressure hits them.
This is the fortnight where an unlimited plan pays for itself twice over.