As someone who is a major believer in watching and supporting legally, and also in the US - right now this is not available anywhere legally for the US. This is a very very common problem with Japanese dramas.
Much like kdramas before, many streaming platforms do not seem to see the appeal and potential for demand for japanese dramas - especially non-mainstream ones. So, just like with kdramas and other countries before, you just keep filling out title request forms (Netflix; Viki) and go to fansubbers. When/if they become available on streaming platforms, you rewatch there and hype/share those platforms.
