DTV is not a non-immigrant visa. The TrueMoney app wants 2 photos: "Take a photo of your first page of non-immigrant visa" and "Take a photo of your non-immigrant VISA page in your passport". I've tried what you said but as the screenshot shows, it shouldn't work. That being said, this is Thailand...🙃
I just installed and registered TrueMoney with my passport and Thai number. Transferred in 100 THB from my BB account and tried to do a PromptPay purchase. It didn't work. I called in (1420) and they said I need to upgrade, which for foreigners means a non-o visa or Thai driving license. How did you "unlock all services" to access PromptPay on a DTV?