Significant chunks of the software engineer community self select into minimizing time spent with customers or even any non-engineers. It's understandable but unfortunate too.
I would suggest looking for people that were initially hands on but converted to sales engineer or professional services roles. Some switch because they don't like the programming. Some will quietly be very good engineers that have seen a lot of scenarios.
You'll have to pay a premium for travel if you want to get experienced people that have families at home.
I would just call them "enterprise integrators" or "system integrators", according to my understanding this is what the palantir guys are doing: Customizing the integration at the edge, since its a complex task they call them "FDE"?
We actually don't want them to do exactly what the Palantir FDEs do. They will be customer-facing, but we're looking for people with a high degree of coding skill. We're getting lots of people to apply who have the customer-facing experience but barely any experience with coding.
Are you sure you're offering a competitive salary?
I think so. We've done the research on it. That doesn't mean we shouldn't revisit the salary, but I think there's a fundamental mismatch between what we're asking for and who is applying.