Each has its advantages and disadvantages. Self-study, you have to have this perseverance. When you encounter a problem, it may take some time to solve it, or you don't know how to solve it at all. I will feel irritable. Although I feel energetic at first, I may not be able to calm down when I really study by myself. I'm from college, too. As for training, it seems that there is only time on weekends, and there is not so much time from Monday to Friday. The advantage of training is that someone can teach you and there is a learning atmosphere, which is still good, but you should also be patient. You are too free in college, afraid that you can't stick to it. However, from training to entering the company, there are still many things that are not understood. After all, I just train some common tools.
I remember having a part-time job when I was in college. I definitely need to practice more when designing this work. You can find some design companies or study in design companies, which I think is better than training institutions. You should do it according to your own situation, but no matter which one you choose, you must have this patience. Don't be full of energy and lack of stamina. This is just my personal opinion.