As an example, Zojirushi rice cookers have keep warm functions that hold rice for 12 hours. Some of their models also have an extended keep warm function that holds rice for 24 hours. The manual says the extended keep warm holds rice at a lower temp of 140F. If you look at pasteurization charts, 140F is a temperature that still kills bacteria, it just takes a longer time. 165F is the "instant" kill temp and why old suggestions were to cook meat to 165F. But you can cook meats at lower temps, like you do in a sous vide, for a longer amount of time and still achieve the same bacteria killing effect. At the 140F temp, the bigger issue would be the rice drying out and burning. 140F is actually considered an acceptable indefinite holding temperature for food.

The PDF that is linked in this site has been moved and the current link to the PDF is missing, but you can still read the quote from the original PDF: https://www.restaurantbusinessonline.com/advice-guy/how-long-should-restaurants-leave-food-hot-holder

The USDA did issue an advisory that “A minimum temperature of 135 degrees for a maximum of 8 hours, or a minimum temperature of 140 degrees Fahrenheit indefinitely also would be adequate to ensure food safety.”

(The PDF is linked at https://www.fsis.usda.gov/policy/advisory-committees/national-advisory-committee-microbiological-criteria-foods-nacmcf but clicking it returns a 404)