Success!!!!
Yes, the system is definitely automated. I attached a cropped out QR code for Dose 1 and Dose 2.
I additionally changed Accommodation from SHA+ to AQ Hotel, (on the Accommodation page in the Test & Go section), and it returned a response mail and a Thailand Pass QR Code within seconds.
Thanks to @ Alan2969 (he was the first one I saw mentioning this, could have been others before…), @Pepper9187 for confirmation of this method working, and all of you that have suggested cropping out the QR code from the vaccination certificate and upload that.
I initially applied this Tuesday and got an immediate email response that Thailand Pass had received my application and a result of my application would be 7 working days. After reading here that the system most likely is automated, I figured I’d do a second application.
The only things I changed from my first application was to crop out the QR code from my vaccination certificate and upload that. And checked Alternative Quarantine instead of SHA+
I’d also like to thank the ones that have suggested that if you only have a vaccination certificate for your second dose, then attach the same document and QR code for dose 1 and dose 2. That was my exact predicament, having a European certificate that only has a QR code and date for your second dose.