Lightly spoon flour into a dry measuring cup; level with a knife. With lid off a 6-quart Instant Pot, press [Sauté], and use [Adjust] to select “Normal†mode. Combine flour and oil in cooker; cook 5 minutes, stirring constantly with a flat spatula until dark brown. Add bell pepper,onion, celery, and garlic; cook 3 minutes, stirring frequently. Stir in 3 cups water, Old Bay, garlic powder, salt, tomatoes, chicken, and bay leaves . Turn cooker off. Close and lock the lid of the Instant Pot. Turn the steam release handle to “Sealing†position. Press [Manual]; select “High Pressure,†and use [-] or [+] to choose 23 minutes pressure cooking time. When time is up, turn cooker off. Open the cooker using Natural Pressure Release. Stir in hot sauce and okra. Press [Sauté], and use [Adjust] to select “More†mode. Cook, uncovered, 5 minutes, stirring occasionally. Add shrimp; cook 5 minutes or until done and okra is tender. Remove and discard bay leaves.