I don't know you nor your details, neither you mentioned any. But, just thinking out loud, it might be they think you're not a real remote worker or they didn't trust your papers and gave this shorter visa as a trial test, after which you can get a regular DTV? It might also have something to do with you already having lived "too much time" before in Thailand with visas that weren't supposed to do that?
Participante anónimo 740 Can be extended for up to 1 year, but rather than that, it should apply because one is not sure if when will be the next exit. Could be a few days later, a few months later or even a full year later.