Ok I'll help. Take any of the hundreds of statements by Trump that the election was stolen not under oath.I challenge you to directly quote the alleged lie and prove that it is a lie.
Good luck.
Then take the statements of the highest DOJ officials including Bill Barr, stating under oath that they investigated the various allegations of voter fraud, and found them meritless.
Then you can take the court orders of the judges adjudicating the various lawsuits stating the same.
And finally you can take the court filings of Sidney Powell saying no reasonable person would think her allegations are true, and the admissions of Guliani that his accusations of voter fraud we defamatory. Legally speaking defamatory statements are untrue.
What you have left is Trump's word of stolen election against the DOJ, judges appointed by Democrats and Republicans and lawyers asserting it when faced with lawsuits. That's proven beyond any reasonable doubt.