Behavioral problem. Only. pls guide me!

MY elder son is 11 years Old. After covid school from home for 2 years was created very bad impact on his studies. He is not listening to me at all... not about the studies, having food or abt any work. Arguing every time. Shouting on me or his father if we are telling him abt studies or food. Not at all ready to listen what we are telling to him. Don't understand how to handle him. Is this due to his age or is it normal to this coming generation. He is  always angry with me as and when I am not giving mobile to play games also not ready to buy the things for him when he asked. Actually  I am totally  against giving mobile to kids for playing games. My younger son is 3 years old. He used to play with him.. but now not playing that much. I understand after covid school ad tutions start again . So he is getting  less time to play. But it is for his betterment only. Pls guide me