Thibaut BernardNo need to show any insurance for the DTV. You can self translate docs to English and include the original. No need to use an agent, you meet the requirements for the Workcation DTV you just need to show it on paper it's good to include a cover letter.
You are working and have more than enough in savings so they would not accept the sponsorship. Sponsorship is for dependents and spouses. There are likely to be some changes to the DTV, especially for the Softpower option but it is very unlikely DTV is going to be stopped. A lot of rumors but best to ignore and apply. Bonne chance!
You are able to support yourself so no sponsorship is required. Six months seasoning of the 500k is not required in Paris/Brussels. You can find posts in the threads from DTVERS who applied in those cities. Paris is hit and miss with approval can take upto a month some have got it quicker.
Anonymous participant You will be fine applying from Vietnam. You are correct they are used to it hence so many go there and get approved with no problem. triple check your docs, before submitting.