While the rice is cooking, prepare the filling: Finely mince the ginger. Finely dice the mushrooms and bamboo shoots.
Heat the oil in a large nonstick skillet over medium heat. Sauté the ginger until fragrant, 2 to 3 minutes. Add the mushrooms and cook, stirring occasionally, until fragrant and golden-brown, 3 to 5 minutes. Add the bamboo shoots and stir-fry just to combine.
Add the soy sauce, Shaoxing wine, vegan oyster sauce, sugar, umami seasoning, pepper, and salt. Stir in 2 cups of water, then add the steamed rice.
Using a silicone spatula, gently press and toss the rice until all the grains are covered with sauce, about 2 minutes. The texture of the rice should be soft—if the rice appears to be too dry or undercooked, add more water, 2 tablespoons at a time. Taste and adjust the seasoning accordingly. Set aside until cool enough to handle.