ask them if they will provide a eork permit for you after the course 🙂 There might be some freelance work when the tourists come back but without work permit it is illegal.
You are most likely not able to get a work permit as a DM unless you have somekind of another role in the company which hires you and is willing to apply the work permit for you.
unless you are doing an instructor course you cannot really legally work in diving industry in Thailand. And at the moment most instructors who are still here do not work in diving, no customers. Hopefully this will change.
[the] terms "America", "American(s)" and "Americas" refer not only to the United States, but to all of North America and South America. They may be used in any of their senses, including references to just the United States, if the context is clear.