You'll never get self service out of a company that works this way. But it's not all bad. Behind the salespereson is an engineer who knows the product well and

You'll never get self service out of a company that works this way. But it's not all bad. Behind the salespereson is an engineer who knows the product well and is paid to impress you. Use that to your advantage. Tell them what you want and let them put on a show! They are very likely willing to invest multiple engineer-weeks in helping you build a POC in their environment, fielding your questions, etc. The initial contact may start from the assumption that you're a bureaucrat but once it's clear what you're interested in and what kind of evidence is going to be persuasive to you, a good sales process will play ball.