It sounds like you have an international - international connection? And any baggage is checked through?

Assuming you want to stay in the international transit area then your options may be limited? Many, many people spend the night, so assuming you do not want to opt for a "day"-room, then maybe scout out one of places where they have the recliners - one area on level 3 near the DEFG intersection - or a row of padded chairs - which are all over.

If you can "enter" Thailand easily - visa exemption rather than a VoA - then maybe a local, inexpensive hotel is an option? But this may present additional challenges re: clearing Immigration, Customs, Immigration (again), and the associated passenger service fee, which might not be an issue?