Curious, looking at your photos, how long has it been since you came in on a tourist visa?
Not 6 months, continuously. Unless you have a long-stay Visa. You can technically leave and come back every on 60-90 days visas. But that looks sketchy to Immigration. They look for it.
If you do stay 6 months in any ROLLING 12 months. That is all you can stay.
It is still considered an international booking even if the first leg is in the same country.
The first boarding will check everything.
That being said, I would have all documents I may need just in case. Who knows, yesterday's rules may not be today's rules. And in Thailand, everyone does it differently.