I’ve flown Lufthansa from Germany to Western Kazakhstan on the NEK cabin and while uncomfortable… it’s doable. Ditto for Aeroflot from Moscow to various places in Central Asia (Osh, Bishkek) on their 737s and 320s, or UIA from Almaty to KBP. Flight times were all north of 4 hours or, in the case of UIA, more like 6 hours as they had to avoid both Russia and the Donbass.