Cut off tops of tomatoes, leaving a corner still attached to create a lid. Scoop out insides of tomatoes and transfer to a large bowl; squeeze juices out of tomatoes.

Cut off tops of green peppers and reserve for later use; scoop out seeds and membranes.

Arrange tomatoes and bell peppers in an 11x17-inch baking dish.

Preheat the oven to 375 degrees F (190 degrees C).

Heat butter in a large skillet over medium heat; cook and stir onion and garlic in the melted butter until softened, 5 to 10 minutes. Add ground beef, soy sauce, seasoned salt, and black pepper. Cook until beef is browned and crumbly, 5 to 10 minutes.

Mix squeezed tomato insides and water into browned beef mixture; bring to a simmer and cook for about 15 minutes. Add rice and bring to a boil; remove skillet from heat.

Spoon beef-rice mixture into tomatoes; place tops onto filled tomatoes and arrange them into the baking dish with lid sides down.

Stuff bell peppers with beef-rice mixture and top with reserved lids; lay bell peppers sideways in the baking dish. Pour olive oil over stuffed tomatoes and bell peppers; season with salt and pepper.