In addition, I feel that there is something wrong with your practice method, especially the light weight. You know, if you want to grow muscles, you have to use a weight that your group can only do 8- 10. If you work in groups of 25 people, you will be exhausted, and finally you will increase your endurance.
You can find a muscle net with a lot of professional training knowledge online, study hard, and then make a scientific and suitable plan for yourself.