Some confusion here. The limit is 0.2% llimit snd seemingly applies to extracts, ie sweets, oils, resins etc, not the plant itself. That's not to say there won't be a lot of flipping & flopping when the legislators finally get their act together. For for now see:
https://coconuts.co/bangkok/news/blunt-truth-media-keep-getting-it-wrong-on-thai-cannabis-legalization/ or
https://www.expatden.com/thailand/cannabis-in-thailand/