There's an interesting "Search Engine" podcast (in English)[0]. Apparently a lot of the people doing the actual scamming are human trafficked and being held in compounds against their will.
From what I understand, a number of them are Chinese nationals. I suspect that taking Chinese slaves might not be a great idea. China tends to carry a big stick; especially in that region.
Wouldn't surprise me, if the DOJ had some "under-the-table" help from Chinese sources, but not in any way that anyone can prove.
China permitted/sponsored rebels to seize a decent chunk of the Myanmar side of the Chinese/Myanmar border after a number of Chinese citizens (allegedly including some undercover Chinese police) were killed in a scam compound there.
Except it seems it's Chinese Nationals running the operations in the first place, who undoubtedly have connections to the CCP to tacitly look the other way.
[0]https://www.searchengine.show/whos-behind-these-scammy-text-...