The Florida constitution allows the governor to remove certain state officials for “misfeasance, malfeasance, neglect of duty, drunkenness, incompetence, permanent inability to perform official duties, or commission of a felony.”

This is the second time in as many years that DeSantis has removed an elected Democratic leaning State Attorney because they didn't want to prosecute based on DeSantis' unconstitutional laws. I believe that this is the first time he's just appointed a replacement, which is super illegal.