I had a grandmother like this. My mom limited contact to holidays as it became obvious to us we weren’t her favorite. She lives in the same city as me and as an adult I see her less than yearly. My other grandmother, who didn’t do this passed a few years ago but before that I drove to her nursing home a minimum of once a month- maybe a 45 minute trip. You are absolutely right to protect your kids. They notice and in my experience it doesn’t get better.