It is very important to mould and control the tender minds of our children. I was facing the same issue. Staying in a joint family, I was always occupied with either house-hold work or office work. To keep my child engaged and not disturb me, I introduced her to TV and Mobile phone particularly YouTube. Eventually I realized, for me to keep her engaged in eating or any other activity, she would not do anything easily without accessing my phone. Even while sleeping in her cot, she needed a mobile phone. It was my mistake, not to blame my little one. So I slowly and steadily started deviating her with other activities like colours and books with various colourful pictures.
I would sit and colour with her, play games with her, recite poems with actions, take her to the garden, enrolled her for a toddler class where she would learn interaction and communication with other kids and so on.
I kept her busy in other activities all the time and eventually accessing mobile phone was only restricted to sleeping time. I also started bed time stories and it worked too.
I am sharing this experience for you to be able to make the right decision for your children because it took a lot of time for my little one to overcome her addiction.
Even staying physically staying active is important. Most of the clubs offer summer coaching. Identify what is your child's interest and encourage them to move ahead in that field.
Thanks & Best Regards,