I don't need to do research. There's no new visa. There's a digital arrival card, similar to the old paper one. It starts 1st May. It is not a visa, and many people are telling you this. It's not us who need to do research.
There aren't any new visa requirements. I'm curious why and where people are reading the word "visa". We used to fill in paper arrival cards, they weren't visas, and aren't visas now. But am I missing some wording on the link?
it's on the Thai TDAC site. It's very clear. No point splitting hairs over using the word should: the word is used in auxiliary function to express obligation, propriety, or expediency.
So you "should" do it within the 3 days before arriving in the country or you won't be allowed in.