All 3 of okra, filé (sassafras) and roux (flour cooked in oil) operate as a flavoring as well as a thickener. Of them, roux is the one most universally available.
Filé can be bought online, but I don’t like Amazon.🤷🏾♂️ So you’d have to find your own spice vendor. Penzey’s, maybe?
Roux...