At some point, once the SCOTUS has told them they have to "facilitate" his return (which they have), even Trump needs to just say, "oops" and fix the problem instead of trying to double down on a mistake, one that even they have said was a mistake.
Now we are getting to a level of obstinance that will simply allow this guy to stay once all is said and done, if they had just had the hearings the courts ruled they should have. You know, hearings to prove they are actually members of the newly minted terrorist organizations list, they likely could have deported him elsewhere as deporting him to El Salvador was not an option. Now, because they keep trying to avoid responsibility, it is likely this guy will be a guest of the US for a long time time come.