Dice the chicken breast into bite-sized pieces and slice the andouille sausage into thin rounds.
In a large heavy-bottomed pot, heat the avocado oil over medium heat and whisk in the cassava flour to create a clean-eating roux, stirring constantly for 5-7 minutes until it reaches a golden brown color.
Add the diced onion, green bell pepper, and celery to the roux and sauté for 5 minutes until the vegetables have softened.
Stir in the minced garlic, Cajun seasoning, dried thyme, sea salt, and black pepper, cooking for 60 seconds until highly aromatic.
Slowly pour in the chicken bone broth and tomato puree, whisking to ensure the roux is fully incorporated and no lumps remain.
Add the chicken pieces, sausage rounds, and sliced okra to the pot, then bring the liquid to a gentle boil.
Reduce the heat to low, cover the pot, and simmer for 25 minutes to allow the flavors to meld and the okra to naturally thicken the broth.
Place the cooked brown rice in a bowl and ladle the hot gumbo over the top to serve.