Your skepticism is not unwarranted, but maybe this video explanation of the DOJs argument in this lawsuit will help open up some optimism for you and any other skeptics:Please explain what argument the US DoJ has made (or can make) that haven't already been made by other lawsuits on the same matter.
And the US DoJ just being the US DoJ is not an argument in and of itself. On the contrary, with the rapid demise of most skilled attorneys from the federal agencies, and the laughable and baseless lawsuits the DoJ has been throwing at all the walls like spaghetti, their filings will be read with a jaundiced eye. I see the whole idea of the US suing states over already settled matter as nothing other than political grandstanding and campaign advertising for republicans.
TLDR; this lawsuit has some teeth to it with serious implications for potential success and subsequent relief