Hi – the best way to avoid EMF exposure from electronics is to create distance and reduce the duration of use.
So avoid putting phones in pant pockets for example, or using wireless headphones or wearbable devices with WIFI enabled. Get your kids used to putting their devices on airplane mode if it’s near their body and not in use. Get wired headphones and preferably shielded ones too.
I bought my kids the Defender Shield pad for their iPads and laptops. They have many other EMF protection tools too that you can browse through their site.