AT&T disconnecting from home wifi

I have a Samsung S9 plus. Recently my phone has been disconnecting from my home wifi. I haver to restart my phone so it will connect again. I have tried forgetting the network and signing in again, most times no go. AT&T support says each time I enter my home, I must disconnect mobile data and turn on wifi and when I leave my house I need to turn off wifi. My phone was fine until recently. Before I start turning on and off these controls each time I leave my house, I will switch to another carrier if I have to. The explanation of what I have to do is ridiculous. Please help.