Have you tried LinkedIn? From my anecdotal evidence, AI experts are the largest group there right now.
Irony aside, finding an expert for anything is difficult. Not because they don't exist, but because there's a lot of charlatans aiming to profit from the non-expert not really being able to tell. Do not underestimate their ability to BS even smart people, at least for a while.
My approach is usually to just ask around until I get a recommendation, a web of trust model if you will. I could for example recommend what I'd consider an AI expert to you. But you don't trust me because you don't know me, so by extension you have little reason to trust them. And that's what I'd advise: Find someone you trust, directly or by proxy.
If that's not a viable path, I would personally look around and try to figure out where relevant people hang out, write to one of them out of the blue. It appears people are more helpful to strangers than I previously assumed, though many do ghost. Many people have reached out to me this way, and I've sometimes ghosted them for embarrassing reasons like forgetting to answer, I've never once been annoyed by someone asking for my help.
I always offer payment, no matter how I found someome, based on the rate they name. I find that respectful, and some respectfully take it, others can't be bothered to write an invoice, and prefer to just do it pro bono. Though since you said it's intense, I would probably insist on paying them :)