Why won’t the realtors I talk to accept a Small estate affidavit to transfer the title of my deceased mothers house?

My mom left her house to me in her will. I have 3 brothers that are also in her will. She left her car to one brother and anything she had left is to be split equally amongst the four of us. Aside from the brother that gets the car, one of the other brothers is deceased and the other brother doesn’t want anything she had. In other words, there’s no dispute over anything in the will. My mom only had her house, her car and a little bit of jewelry(also left to me). Her house has a reverse mortgage lien on it that has to be paid. I want to sell the house and pay off the lien. I don’t want to go through probate when her estate is so small and nobody is contesting her will. The problem is the realtors I’ve talked to say that they won’t take a small estate affidavit and that I need to be appointed as personal representative before I can sign their listing agreement and they can go to the title company and open escrow. Isn’t there an easier way to do this without having to go through probate?