Ask HN: How to connect with experts outside of the tech domain?

I had an idea that came about after a dinner with an acquaintance, where he told me about the time he used to work as a professional chef. An interesting thing I picked up on was a decision making process that chefs go through by eyeballing some numbers and just going by their gut feeling. I thought the decisions could be made faster and more accurately if the users had an app that showed how their choices would affect their costs in real time. I even put together a small demo, and I think the recovery after the pandemic would be a good opportunity for restaurants to save costs by removing some inefficiencies.

The problems is I have no contacts in the business so I have no way of knowing what users actually need, and whether they would even be open to using insights from an app. Normally that would be the end of it, because I have zero experience in marketing to that sector. But I'm wondering if there's a way for me to get in contact with people in the restaurant industry and see if they'd be interested.

Are there any strategies for making contacts in domains outside of your own? How can you find people to work with you who aren't in tech?