You are correct. The lower light assembly cannot be easily removed but, with a few contortions you can get at the reversing light bulb and the rear fog light from under the car, negating the need to remove the assembly. A while ago I posted my experiences adding additional reversing lights to my 2018 Kona. The post included a couple of pics showing the rear of the fittings taken from underneath the car. What you need is a trained octopus to get one of its very dexterous tentacles up to the back of the light assembly and unscrew to bulb fitting. If you don't have a trained octopus readily available give it a go yourself. It ain't easy but it's doable and a darn side easier than removing the inner guard etc.