One useful tip I got from a friend in sales: open the call with an offer to set up a call at a more convenient time. It seems strange to immediately ask for another call, but it is really helpful in showing that you're friendly/flexible, and you recognize that the person you're calling is busy.
About 30% of the time, the person was happy to chat in the moment (they had chosen to answer a call from an unknown number, after all). And the rest of the time, you benefit from setting up a time that is more convenient for them. Some of the time you end up never having the later call—but it seems this happens where there wasn't a great fit to begin with, so it actually saves you time talking to an unlikely lead.
About 30% of the time, the person was happy to chat in the moment (they had chosen to answer a call from an unknown number, after all). And the rest of the time, you benefit from setting up a time that is more convenient for them. Some of the time you end up never having the later call—but it seems this happens where there wasn't a great fit to begin with, so it actually saves you time talking to an unlikely lead.