Ask on Reddit : /r/FPGA Be specific about your timezone (or where in the world you are), how long you would want to interview for, and method of talking (email, messenger, zoom, teams).
Somebody will answer. They will usually be overly keen sort, happy to talk about their favorite topic.
Be aware that most FPGA work will have some sort of Non-Disclosure Agreement (NDA) involved, so people can't talk about the projects they work on, just about the sort of work people do.