3.5 year old cant seem to entertain himself

I need some advice.

I’m a stay at home mom to two (3.5 and 1.5 yr old boys). I also work from home running a creative business and I also am writing a novel. In the mornings I let my kids have free play while I do some work in the living room with them. My 1 year old will play and watch cartoons happily but my 3 year old will not/cannot. He whines and cries at me to go outside or play with him. If I take them outside he also will not play. He will stand there and whine or throw dirt on me or his brother. If I provide him with an activity like coloring he just breaks the crayons or tears up the book. If I give him a box of toys or things to do he will just whine at me to play with him. He will tug on my leg, cry, and roll around on the floor all morning while I’m trying to get work done. He will also start harassing his brother who plays independently very well. He will hit him or take his toy just to be mean/get a reaction from me. I’ve tried to explain to him that it’s “Lucas play time” but he tells me “no!” and just refuses to play by himself or with his brother. He is ONLY happy when he’s being entertained and played with.

I’m so frustrated that I enrolled him in preschool for 3 days a week, but since we live in a small town, there’s not a spot for him until August. My husband is also against putting him in preschool and says it’s unnecessary/waste of money.

But I can’t get any work done. I can’t find time to work out or even make myself a decent lunch during the day because my son cannot entertain himself for even five minutes. He even follows me into the bathroom and whines to “stop peeing and play trucks with me”. I only try to work in the mornings and I give the kids full afternoons of activities.

What can I do?