They can bring up that other states are breaking the constitution, and all their cases go directly to SCOTUS because it is a state on state issue
Yes and no. The Supreme Court is the court of original jurisdiction in disputes between state governments themselves,
but this does not mean that SCOTUS will automatically accept and rule on every case so submitted. The Court has the authority to
decline jurisdiction and thereby quash any such case with no possibility of any appeal, and has exercised this authority many times in the past.
In addition, once acting as the court of original jurisdiction, SCOTUS will handle the case
in full, performing all the same functions as a trial level court normally would; therefore, standing would have to be established and all other legalities satisfied. There is no automatic pass "because plaintiff is a State".