Choices: it’s wonderful to have options. And good for you for getting the interviews! I don’t work for either one.
What is your personality type? Where are you going to feel more comfortable? The Asian carrier will probably be much more structured and the leash likely tighter. Does that appeal to you? Their operation will probably run more in a clocklike manner. Socially you may find yourself more segregated.
The Middle Eastern carrier offered the heavier jet, probably has more expats employed making the social scene more open. Where do you want to be in 3/5 or 10 years? Do you want to be possibly looking at a heavy jet upgrade or relegated to your first officer “duties” in the right seat of a 737?
What previous international experience do you have? Did you enjoy it? Go to both interviews educated on the cultural nuances, in as much as you can learn them in the time you have to work with. Let them know you appreciate the opportunity to work for their world-class industry-leading airline. See what you get offered and do what you want.