I found a used IS350 at a local Kia dealer; low miles. I had the salesman (kid; about 19 years old if he was a day ...) bring the car around. I sat in the front and it was very nice and confortable. I then got in the back (or attempted to), and it was crazy cramped. I really like the IS car but there's no way I'd subject any normal adult to more than 20 minutes in the back seat. Kind of a let-down, as I "wanted" to like the car. But there's no way it would work for my purposes.
True to any sales position, he then said "Have you seen our new K5?". OK - I'll play along ... Let's go look at the K5. I must say, in terms of interior room, it was very generous both front and rear. There was more room in the rear seat area (especially leg room) than my 2018 Taurus! Very impressive car in terms of interior volume and design. However, there are only two engine choices ... 1.5L turbo which can be had with AWD, or the 2.5L turbo which can only be had with FWD (and has been panged by many reviewers as very difficult to control due to torque steer).
Sooooooo ..... my search continues. May have to look at a ES350 F sport (more torque steer), or I'd really like to see a TLX Type S, but there are none in my area (new or used).