Easy to live on sub 700$ a month if you're happy with air conditioned studio, mostly asian food, scooter and not going to high end bars.
Get the 1 bedroom apartment, quite often takeaway/delivered western food sub 1500$ a month.
Go eat out western food everyday, live in a 3 bedroom in the nicest district go to fancy bars etc and yeah maybe you can reach your 5k a month...
People have no clue / are not willing to experience adjustment for 3 weeks... But easily possible to live here for budgets mentioned above...
Plus health insurance like Cigna for $100-200 unless you want to pay $10,000-20,000 in vinmec if you crash on a motorbike or get other serious sickness.
Plus border runs like $200-300 three times a year or often for cheaper depend on your paasport.
Problem that I doubt its how average SWE on HN imagine "comfortable" living.
Then if you have a partner who is not remote worker and kids there will be other surpeises for you.