Open house tactics

Looking for some insight from other loan officers.

I know my primary client is the real estate agent since they're the ones referring business to me. That said, I also will co-host open houses as a way to build relationships with agents, and if I happen to pick up a few buyer leads, that's a bonus.

The challenge I'm running into is this: I have conversations with buyers at the open house, we build some rapport, and they willingly give their contact information on the sing in sheet. But when I follow up on Monday or Tuesday, they either don't answer or become flaky.

The frustrating part is that many of these buyers are pre-approved with lenders whose pricing and fees are absolute junk Think cross country and G Rate kinda pricing. In some cases, on a 800k loan I know they are paying $16k or more in BS

For those of you who consistently convert open house leads, what has worked best for getting buyers to at least let you run a comparison or complete an application? Is there a particular script, follow-up strategy, or value proposition that's helped you break through the "I'm already pre-approved" objection?

I'd love to hear what's been successful for you.