If I "swipe down to reject", will caller get a chance to leave voicemail?

A few times a year someone who isn't in my address book might call me, but every day I get several spam/scam calls. So basically anytime I see a plain number, I swipe down to make my phone stop ringing. I've been assuming this sends the call straight to voicemail (so that if it is legit they can leave a message) but it strikes me that "rejecting" a call might hang up completely on the caller. What happens when I "swipe down to reject" a call from the homescreen? Is there a way I can quickly ignore a call while still leaving the other party a chance to wait for it to go through to voicemail? This is a fairly stock phone, an "Android One" Moto x4 bought from Google Fi but it does have some extra Motorola tentacles on it. (I'm also interested in doing this automatically, but only if it uses a built-in feature and **not** some random app that *you* happen to trust, sorry.)