1. This case doesn’t hinge on showing evidence of vote fraud, which could have been wiped or shredded by now.
It’s based on the defendant states letting officials unilaterally change voting laws that only the legislature has the power to change, which means the vote tallies, whether fraudulent or not, were derived through illegal and unconstitutional means.
In this case, the argument doesn’t depend on whether fraud can be proven beyond a doubt, but on the undeniable fact that laws that made fraud easier to commit were created unconstitutionally.
2. Texas is not asking that the election be handed to Trump.
They are asking the court to order the states to give the duty of selecting electors to their legislatures because that’s what is required under the Constitution when the vote is tainted by illegal and unconstitutional actions, which the lawsuit clearly describes (for instance, officials unilaterally changing ballot laws that can only be changed by the legislature, or imposing different standards for accepting ballots in Democrat-run counties than in Republican counties.)
The legislatures are free to choose Trump or Biden electors, but at least then, the choice will be made legally.
3. Texas has standing to sue the other states over this because, just as the House represents individual citizens, the Senate represents states.
The national election also picks the vice president, who settles any tie votes. That means that any illegal actions that affect the results of this election also affect all states through control of the Senate.
4. As for the argument that the SCOTUS would be taking unprecedented action to interfere in a national election, the suit cites numerous quotes showing precedent for the plaintiff’s arguments.