The DTV to wrap your head around correctly in one sentence:
The DTV (Destination Thailand Visa) is in effect an extended / longer version of the METV (Multiple Entry Tourist Visa).
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Explanation:
With the (good old) METV, you got a visa that was valid for 6 months from the day it was issued and allowed you to enter Thailand during that period an unlimited amount of times for up to 60 days on each entry. It is possible to extend at local immigration in Thailand to stay an additional 30 days on each entry before having to leave (and possibly re-enter) Thailand.
Requirements for the METV are: Proof of a certain amount of saving in the bank account + proof of need for multiple entries.
Now the DTV is the exact same thing. Only that it is issued for 5 years from the day it is issued and allows you to enter Thailand during that period unlimited times for up to 180 days in each entry. It is possible (but optional) to extend at local immigration in Thailand to stay an additional 180 days before having to leave (and possibly re-enter) Thailand.
Requirements for the DTV are: Proof of 500k THB in savings + proof of either a remote work abroad or an (likely extended) participation in a “Thai Soft Power” activity.
As with the METV, the DTV (unlike the LTR visa) is not meant to establish residency in Thailand. Though just like people used the METV, with which most people maximized their stay in Thailand up to 6 (or even close to 9) months with border runs, so will they with the DTV, only this time for up to almost 6 years.