If it doesn't appear to be easy, you likely can't.
I believe iOS only allows you to change the name of Bluetooth devices that are capable of it and permit it. The bluetooth "friendly name" you see is representative of the products description, model, series, etc, usually something friendlier like "Samsung Headphones ModelXXX". In your case its 17AHU which like means 2017 A=something HU=Head Unit...or something along those lines which is more of a descriptor for Honda not you.
What iOS does not allow is an arbitrary name change. This is what MacOS, Windows, Android (sometimes), etc can do. This is just the phone seeing the real name but displaying it with what you want to see. Other people would still see the original bluetooth name.
I'm not sure why Apple does provide this, maybe something to do with cloud sharing or something. Regardless if you can't find a setting in the vehicles menus its likely not possible, or at the least not easy.