In your situation, Cambodia 🇰🇠is best suitable and Kampot will be your haven. Cambodia won't ask you show money, no income tax so on. You only pay under $400 for 12 months visa fee. I have Australian friend living there same age as you. If you want more info inbox me
Just live boyfriend girlfriend cheaper. Otherwise after marriage she will want you to buy a family home which your name can not be added in property ownership by law. And she can kick you out anytime and her real Thai man will move in.