1, your malnutrition is the main reason. You should eat all eggs, meat, rice flour, fruits and vegetables in moderation, so that you will not gain weight, but also make your body better. 2. Your previous training focused on losing weight, and you didn't pay attention to the combination of strength training. I suggest you practice dumbbells, equipment and other strength training, and stretch well after training. I don't recommend eating protein powder or muscle-building powder specially, because these things are for professional athletes, because they train too much every day, and they want short-term effects, and don't care about the harm to their bodies afterwards.

Finally, I want to make a general evaluation. I think the duration of your exercise is appropriate. Generally speaking, the duration of your exercise is about 1 to 2 hours. I suggest you change some exercises, or shorten the time of some exercises, increase equipment, and attach importance to the combination of strength training and fat reduction training.