I think it’s less about the specific toys, I think it’s just something that “clicks” with them, or a development leap, whatever you want to call it! My son has just started to do this a lot more. It’s always imaginary play, sometimes with Mega Blocks/ Duplo/ Stickle Bricks but often it’s with random items like an empty box or a piece of string x
My son is the same, struggles to play alone. I’m getting him some magnetic tiles from Amazon that look good