I think you do not have to and should not leave the key in the ignition. I have a 2017 wrangler and the book in the car says to do same as you said. . Reading the fine print that comes with Jeep says the complete user manual is on line. The “real” on line manual is different. There is no steering wheel lock so the ignition is left off and the key is removed. I raised he double lwith Jeep over this when I first purchased it butThey did nothing and did not care. This is the third Jeep I have towed and every one was different. Not sure if yours is like my wrangler but it’s worth checking. On edit I have never had a charge line to any of the jeeps I’ve towed and have left the Jeep connected for as long as 4 days when traveling, I use the brake buddy as well and I have never had the Jeep battery run down
