quick update on the ThiaPass website; I used Microsoft Edge browser, Chrome kept giving me the API error, even after installing the CORS extension. I submitted screenshots of all original documents - to keep file sizes to a minimum (the website they wrote are pretty fragile) and got my ThaiPass QR code immediately, no waiting time, it did get sent to my spam mailbox, but I got it.
**(for double dose of Pfizer in EU I just reuploaded the same certificate for both doses - I only got a vaccine certificate after my 2nd dose + separate screenshot with QR code)