Regarding the UX... this is probably my American POV, but it is just such a badly compromised car that it's great at nothing aside from maybe MPG with the 250h powertrain.
I know these lower rooflines and chopped down D-pillars help reduce drag and look "sporty," but they also drastically eat into head and cargo space, which is a big part of why people buy CUVs over cars. You go look at a "crossover" and pop the hatch to see less cargo space than you would get in a comparable sedan and it's like....???why???
Also factor in ground clearance that is only fractionally higher than an IS or ES, and neither engine even cracks 185hp... it is all wrong.
For it's footprint, the UX does feel very small to me - due to poor packaging, at least for this market where people want cargo space and "macho" looks. The rear seat is almost impossible, the cargo area could barely accommodate a grocery run and headroom isn't great. Just like the C-HR, the UX is the wrong product for this market which is fine because they were not primarily developed for North America. It is also why Toyota is bringing the Corolla Cross here this year, and I think Lexus should do something similar to replace the UX or call it second gen UX here in the States.
I have wondered if the mystery CUV from the Direct4 video could be something like a UX replacement for markets where it has been unsuccessful. I know I've said it a few times, but I think Lexus "best" product line for SUVs would be something like:
"Rugged": ?X > GX > LX (?X = Compact sized, upright crossover but with rugged design like the Lexus version of a Bronco Sport)
"Sporty/Versatile:" UX > NX > RX > TX
Premium Style/Performance: RZ > LF-1 Limitless (LZ?)
I still very much see a place for a CUV under the NX, but UX is not the right vehicle to occupy that spot here in North America. Notice how the second gen Audi Q3 became more upright with a taller greenhouse vs 1st gen, and the X1 has always had more traditional CUV proportions vs. looking like a wagon with an extra inch of ground clearance, like the UX. That is the right approach here.