re: Shrimp Gumbo - how to fix chewy shrimp?

Otis is right on this one as much as it pains me to say so.

The seafood in seafood gumbo cooks very quickly and doesn't add much flavor to the gumbo. You need a strong stock. Ask your seafood folks to save shells for you when they're peeling shrimp for a few days. You can make a nice strong stock with those. Heads make it better, but sometimes, you don't have access. Some folks roast the shells a bit before simmering for a deeper flavor.

Shrimp do not reheat well in gumbo. Add only the amount you will use at serving time. You can add more for a fresh bowl when you eat the leftovers. I freeze the gumbo sans the seafood. It doesn't freeze well in the gumbo either even uncooked is not a good idea.

Drop in the shrimp and they're going to be done by the time you get your bowls ready to serve. Turn off the heat after a minute.