Probably a stupid question but have you tried to adjust the seat by tilting it rearward raising the front edge? At 6'3" it is the first thing I have to adjust in most any vehicle if I am going to be driving any distance at all.
In regards to side bolstering I guess it's personal preference. One of the things I liked about the qx is the lack of comparably. The side bolstering is the first spots to really take a beating if you are in and out all day of the vehicle. They also collapse quickly and leave you with a deformed uncomfortable driving platform with no options to adjust.
Just my opinion fwiw from driving anywhere from 30-70k annually for the past 15 years.
Of course my size doesn't require a lot of side stability at 275. Lol. They don't normally mold seats for my shape. Or maybe they did in the qx which is why you don't have any?