In that case, SCOTUS' opinion would be purely advisory -- and they don't do advisory opinions.
Leaving aside the issue of standing, courts often dismiss cases as "political questions" best left to the elected branches of government, or as "not justicable," meaning that no matter how the court finds, it can't do anything. For lower courts, either of those is a reason to dismiss. For SCOTUS, it's a reason never to take the case to begin with.
as for just re-signing the laws... considering the laws were pushed by a pretender, or worse, i’m not sure that would go as smoothly as just re-signing
You misunderstood me. There's no provision in the Constitution for the president merely re-signing the laws; there is no provision for undoing a presidential signature. They would stand as passed until and unless they are repealed.
point being, they would never have been signed by the president, if the current occupant were to be found ineligible... thus never truly the president