I dont think Non-O has become STV. I think the only difference with Non-O, post covid, is the insurance requirements. I have a buddy that uses retirement visas and he complains about the insurance... But I am not familiar with the Non-O process.
I just pulled my tourist visa from Los Angeles. There form has several options. The only two applicable to me was the STV or TV. It appears the Multiple Entry Tourist Visa is now the STV, which require bunches of paper work. I don't know anything about non-o's
I just went through this process. I booked through agoda. I recommend booking directly from the hotel.
You will need a letter from the hotel that says you have, Airport transfer, 2 tests and 7 days accommodation. After I booked through Agoda I couldn't get anybody from the hotel to respond to my messages. Eventually I had a Thaifriend contact them and it became more complicated.
I recommend contacting the hotel before you book Make sure you can find a hotel where people will be responsive. Book the hotel, get the letter, etc.
My hotel eventually made all the arrangements for me, PCR tests and airport transfer.