Travel insurance is very good value for as long as you can get it for. After you've been overseas for a year, you won't be eligible any more. Get it while it's still available to you.
Travel insurance typically covers accidents + emergencies, which is all the cover you need assuming you're from a country with socialised health care. You don't need cover for long-term illness, because you'd presumably return home if you fell seriously ill.
is it though. If they say "working prohibited" but online work is ok, that very much suggests that online work does not count as "work" as far as Thailand is concerned