I think it depends if you are vaccinated because I came through two weeks ago vaccinated and was free to go anywhere in the airport. There were very comfortable recliners near the windows you can lay down in and sleep or chill. And a small table with a charging station for a laptop, tablet or phone. You may need to ask where to find them, they were only in one section. Not everything was open but a few coffee shops and little restaurants were. Enough to be comfortable.

Thank you!

Some do some dont. Mine didnt, it would be advertised if they did I think it's less common.. heres the site

Yes if you do the 30-day visa exemption you get saved from having to go through the unpleasant visa process. Then once you're in Thailand you can get it extended.