I am still a bit new to Lexus but my understanding is that they are all basically the same with slightly different styling.
One of the reasons that I went for the F sport was the 20" wheels. I prefer the look of them although the ride will be slightly more firm (than the 18"). I was actually planning on buying a Takumi in black as I wanted a sunroof but preferred the styling of the F sport and just added a sunroof. I also changed the colour 😀
I like the "F sport" name. It just denotes a different style and I can't really think of a name that I would prefer. A lot of manufacturers have some terrible model names in my opinion (some good cars I would hate to own because of the stupid name 🙈😅).
I agree that the NX is not "sporty". It is an SUV, not a 911 however with 300hp it is not a slow car.