As far as tipping goes, nurses are not tipped for their work. Nor are doctors. Tipping should not be part of the equation as it puts too much variability in the pay for these people. They should be paid based on the risk and the need for their work, not based on the whims of some people.
The market isn't whatever corporations tell you that you're worth.
Nurses and Doctors make a lot of money and have better health protection. At least, they have full health insurance, compared to food delivery drivers. On top of that, medical professional are expected to be at risk.
If you are coughing and you expect someone to risk their lives, by catching whatever you have, while delivering your food, then, be prepared to shell additional for your delivery.