I am grateful that my daughter has always limited screen time for her kids. When I pop in , which is often just for an hour as they live quite near, one of them may be cleaning the chickens or playing in the garden or building Lego (boy, 10) and the girl now just 13 will stay around, but on her phone if her mum and I are chatting. But if it is a “proper “ visit eg around Christmas we all play a board game together.
With my other grandchildren we had a games evening, they chose Monopoly, and they are 13 and 16.
So whilst it is up to the parents to sort out rudeness, maybe everyone could join in a game together for an hour or so, then it is surely ok if they go off after that whilst the adults chat. A bit of effort and give and take on all sides.
How do you acknowledge Easter.