It's what it says, really. I have attempted to add the line "enable_geyser_workaround": true, to my configuration file several times since I am running my server with Geyser, and every single time I start the server to try and actually have the change on it the line just gets deleted from the config file. I don't know why it would do that.

its an old option, all available options are in the file
anything added will be removed
think it's now just choosing or making a compatible model