Also do consider the war in Ukraine and the suspension of Russian overflight; the great circle route for AMS-BKK passes over Russia, so routing around Russia adds to fuel costs. AMS-BKK great circle distance is 9217 km, and the cruise speed of a 787 is around 900 km/h, so that's ~10 hours on the shortest routing. For the actual flight route, you're adding 2 or 3 hours to that I'd guess.