If you’re in the United States, the AES has resources for finding sound professionals in your area. It’s a small-ish community, so if you contact a few people they’ll be able to put you in touch with someone who is qualified if they aren’t.
That said - I’ve had the (dis) pleasure of running sound in an NFL stadium, and I know there is a team of people who work for the venue or at least for the sports teams who play there, and you can get in contact with them. Off the top of my head I know there’s at least a wireless/RF manager who you can get in touch with and they’ll be able to put you in contact with individuals with the stadium.
All that said, to “engineer” the situation - stadiums are quite possibly the most difficult sound reinforcement environment you can imagine, and it’s hell even for RF - let alone trying to broadcast data in the audio spectrum. I’m curious as to what your product can do that commercial wireless from the major players (Shure, Sennheiser) can’t do better, and even those kinda suck in that environment.