GentlePhoenix7380 when you apply for the Vietnam visa, say that you plan to be in Vietnam for a month - if you give your actual planned travel dates (perhaps 2 weeks) and you need to stay longer you would need to do a visa run out of Vietnam and reenter. Sorry I wasn't clear I meant for the Vietnam e-visa.
When you apply for the Vietnam visa give yourself extra time (you don't need proof of flights for visa application).
I'd allow atleast 2 weeks, and ideally book a flexible flight incase you need to stay (or be willing to wear the cost).
You need to stay there until you recieve the DTV, there are a handful of cases where people did reenter Thailand and still get their DTV but if the embassy realises you will be rejected/denied.
You need to click the button to get a PDF with a QR code (you need to print this, theres a service across the road from the embassy where tou can print if needed)
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