Master Slave Configuration for Redundancy

Hi all, i am looking to run 2 pixhawk 6x in a master slave configuration. what i intend to do is to have one main FC and another as redundancy. i asked ChatGPT if it was possible to do that. I got a response to use MavLink via tele ports of the fcs. I did a search online for documentation on how to set up. However, there was no results. Have anyone tried it before and is successful? Or i am open to suggestions to how i should to do it otherwise. Reson for doing this as im working on a 100KG drone project, so iit be great if theres a solution for saftey consideration