It's been mostly great, still getting used to the chaotic traffic in Bangkok. It's mostly easy, lots of people speak english, locals are friendly and most things are available through an app.

I assume you have a korean passport. Lucky it's free for you to apply for the dtv. Dont have to lose any money being rejected. I helped my Korean friend apply with a cooking school in hanoi, no issues at all

I would try to apply at a different embassy if you believe you had everything. Some places are more strict than others. I was approved in hcmc with soft power cooking classes a year ago