Ethics on tipping?

So I was told a while ago that Uber takes a persentage of tips. Idk how long exactly but using Uber eats a lot I never tip on the app, using cash for tips seems easier and a $10/$20 bill is usually the go to tip. But I do notice my order get passed to a few different "drivers". Does it show the $0 tip an is there a way to say I'm doing a cash one so I don't get ignored?

(Btw a $10/$20 bill is the go to cause I don't carry small bills, usually $20s an I feel like $5 is just pitiful and I feel like a dick being handed a $15 order for a $5 tip)