In my experience, each round of scam calls will stop calling once you have answered their call and said no/hung up after a few seconds of listening.

Which isn't really useful beyond getting them to only call once every few months instead of once every few days or whatever.

Everything but political crap and surveys seems to go like this, answering a call and saying no firmly ends that stream of calls.

For the surveys I answer and ask how much they are paying people to take the survey. Then when they say they aren't paying I say I'm not interested and hang up. My hope is that this is superficially annoying for the person doing the survey. Not antagonistic, just enough to remind them exactly what it is they are doing.