Newbie B2B founder. I am doing it wrong I believe with my mvp and idea validation

I’m a technical founder (CS grad) and this is my first rodeo with B2B sales. I’m honestly a bit lost on the "Customer Discovery" side of things.

The Context: I’ve built an MVP for an AI Data Analyst agent. Currently, it only works with PostgreSQL and Supabase. I actually have one startup running a pilot version right now, and they love it. Their feedback is that it makes searching their large queries incredibly easy compared to their old workflow. So, I know the tech works and solves a problem.

The Struggle: Now I need to find more users, but I feel like I'm doing it wrong. I have three specific questions on how to approach this:

The "Tech Stack" Filter: Since I only support Postgres/Supabase right now, should I strictly hunt for founders who openly use this stack? I thought about using job postings (hiring for "Supabase Developers") as a signal to message them, but that feels like a huge "walk around" / lots of manual work. Is that worth the effort, or is there a better way to find these specific users?

The "Ask": How do I ask for a user interview without sounding like a salesperson in disguise? I want to understand their pain points, but everyone has their guard up.

The Offer: I was thinking of offering a 3-month free trial in exchange for feedback/interviews, and hoping they convert to paid later. Is this a bad idea? Does giving it away for free devalue the product, or is it the standard way to get initial traction?

I’m trying to bridge the gap between "one happy pilot" and "an actual customer base." Any advice on the sales motion here would be appreciated.

Thanks.