as I understand it, this is not neccessary if original visa is still valid when I return. It would be neccessary only if I would return after visa expiration day.
My bank is giving me travel insurance worth 20 million THB on my credit card for free. Don't most banks do it? It's valid for 3 months when traveling abroad, after that you have to stay at least 1 day at home, and can repeat it. I did use it about a year ago, they just called a private hospital, best in the area, and gave them open credit for my treatment. I paid nothing in place.
If your credit card company does not provide it, some online bank services like Revolut, with they cheap paid plans (US$ 15 / month) offer travel insurance within the program for free.
Aren't you entitled to visa exempt for 1 month, with possibility to extend for 1 more for 1900 THB?
Anyway, I needed 2+1 months, applied on Sunday via eVisa, got it issued on Wednesday, ie. T+3, embassy in Prague works really fast 😁 Visa process is handled by your local Thai embassy, not in Bangkok.