Challenges to the election of Presidential electors are resolved under state law, usually by filing in state court. I have yet to find a single case where: (1) the proper party (Trump or his campaign or his elector candidates) (2) filed suit in the proper court (state court) (3) challenging the election results based on fraud (4) under the procedure established under state law (5) where the court dismissed the case without hearing evidence.
Every case I've found either: (1) was filed by a party without standing to challenge a state's election results, like a private citizen (like Lin Wood) or another state (like Texas); (2) was filed in a federal court that either lacked jurisdiction or was required to abstain based on long-standing legal doctrines due to pending state court cases, or was filed in a state appellate court that lacked original jurisdiction (this happened in Georgia); (3) made some claim other than fraud, such as the unconstitutionality of a state election procedure; or (4) either the fraud claims (PA federal court case) or the entire case (numerous cases) was voluntarily dismissed by Trump or the electors before a ruling.
Maybe I missed a case and I'm wrong. If so, I'd love for someone to point one out. But if I'm not, then Trump's lawyers and Republican politicians and talking heads need to quit repeating this falsehood because it is doing some real damage. It will be pretty hard to win next time if we keep lying to ourselves about what actually happened.
All the other States needed their legislators to step in and decertify the results until an investigation could be conducted. It seems that in some states, they do not meet after the election or they had restrictions that only allowed the Governor to call a special session. If I were a conservative in those States I would get that changed and require the Legislative branches to remain in session after the election until they certify the results. Then have the Governor sign off on the certification. If there is a conflict, the State Legislations and the Executive branch would have to work that out before certifying the election results. Legislative branches should legally remain in session until they vote to certify the results.
Trump's legal team did a poor job because they chased every claim of fraud instead of remaining focused. Gulliani should have been focused on Biden and stayed out of the fraud. Lin Wood and Powell kept telling us about the evidence that I have never seen. There was no focus, but that may have been because they were juggling to many states with limited resources.