My ex worked at an insurance agent here in Thailand and I heard a lot of horror stories about Thai insurance companies refusing to help their clients or fight them on every baht they made claims for.
Safetywing has been a breeze. I've made 5 claims so far, and every time they have just accepted the claims and made the payouts, no questions asked.
Yeah, that bs ED visa is not a better option in any way. It's not a valid visa as you won't be studying at the University the visa is for, and the agency is just trying to make money off of you, by trying to scare you into it.
Just apply for the DTV yourself or let one of us help you for much less than what an agency would charge.
Just put your own country in both fields. Most embassy employees don't know what country is what, they just see your nationality and that's the only thing that matters.