Imagine apartments built into what used to be department stores, (Oh, you’re JC Penny 203? I’m at Sears 106). Get those old arcades up and running. Set up meal stations at the food court. Once people actually live there, stores will start to move back in.
If I’m unable to finish my life in my own home, that doesn’t sound like a terrible option.
In my country (and I think most of Europe) malls (especially those in more central areas) have underground parking, or limited above-ground parking. There is a really nice one which is connected to a big park in the back. So maybe you can replace the parking lots with apartment buildings, recreational spaces and transit infrastructure and maybe include some underground parking.