Combine 3 tablespoons rice vinegar with 3 tablespoons oil and the gochujang in a medium bowl. Add the beef and let marinate.
Combine the carrots and daikon in a small bowl or jar. Add 130ml rice vinegar, toss to coat and set aside.
Toss the cucumber with 1 tablespoon rice vinegar and set aside.
Heat 1 tablespoon oil in a medium pan or over medium heat. Add the mushrooms with a pinch of salt and pepper and let cook undisturbed for 2-3 minutes. Continue to cook, stirring occasionally, until the mushrooms are tender and browned, (5–8 minutes). Add 1 tablespoon rice vinegar and 1 tablespoon soy sauce. Cook until the moisture has evaporated. Remove from the pan and set aside.
Wipe out the pan, place over medium-high heat, add 1 tablespoon of oil and let the oil heat until it starts to simmer. Add the beef and cook quickly for about 2–3 minutes or to your likeness.
Assemble the bowls starting with rice. Add the beef, mushrooms, drained carrots, radish, cucumbers, steamed pak choi, bean sprouts, and fried eggs. Sprinkle with sesame seeds and serve.
