I should have said for soft power. For remote worker (I also got it that way), they only need you to prove you're a remote worker. But if only for courses, some embassies require it to be over six months. It's embassy specific, tho. Some body said they were granted the DTV with a single dental appointment 🤷🏻
It depends. Where will you apply from? Some embassies, notable in South East Asia, accept hotel bookings and/or selfies as proof of current location. Where would you apply from?
if the OP was referring to that, then this has nothing to do with the DTV, I mean, each visa has different requirements, for the DTV you need to show 500,000B, and then it's good for 5 years.