What should I know about the STV visa extension process in Thailand?

First of all, I wanted to thank you admins for your help and invaluable advice! Second, I wanted to tell you my STV extension process today just in case it helps others in the same situation.

After spending there few hours from 10 AM to closing time I finally got it! Basically the hotel I had stayed at with Test & Go never sent me the ASQ certificate as requested by the Bangkok Immigration Division. They said that as I had entered the country on T&G all I would receive is the Covid test result. As suggested by someone here I emailed Immigration for assistance (I didn't get a reply on this point or any other point, if not just the generic list of documents from their website).

Anyway, I risked it and went to Immigration with what I had, plus documents from my previous stay, just in case.

So, I got there at 10 AM and I must say the queue was moving fast so I was seen about an hour later. All was OK (by the way the Immigration Officer didn’t pay much attention to the hotel bookings, whether they were prepaid or not), but he wanted to see proof that I had paid for the original Test & Go hotel (strange that this information didn’t seem that important when I got to Bangkok first?). I had brought the hotel booking confirmation saying ‘Paid’ and my PayPal receipt but they only wanted to see something from the hotel. This might be my misunderstanding of the payment proof they want though, but again I don’t understand why it’s so important at this stage when I would have not been allowed to get in the country if I hadn’t paid for the T&G hotel? Anyway, I had to leave my spot in the queue and email the hotel to get the information. To cut it short, two emails, two phone calls, and 3 hours later, I got the right documentation, at which point I had to go downstairs to print it and bring it upstairs AND restart the queue. This time I had to wait an hour and a half! I was seen at around 4.25 PM!

Anyway, another member of staff re-checked the information even though the IO from the morning told her everything was OK and after 20 minutes I finally got the extension! I also was told to do the 90 day reporting.

All in all it was a stressful situation considering I hadn’t slept much (and I don’t perform well early in the morning, I’m not a morning person at all!), but thankfully I got there. The insurance was quite expensive so I'm considering if I will extend again after July.