'boredom' is how I'd call it but it has a negative connotation. Being bored is useful, it lets your mind wander and it's where real creativity can happen.

I read "Non-Things: Upheaval in the Lifeworld" recently and since reading that I make an effort to not pick up my phone as much. I'd recommend reading the book, if you're looking for something to do instead of doomscrolling.