What type of proof do you need? Do math algorithims count or do you need to actually witness the votes being put into the count with your own eyes?
Is Trump a liar by your definition and 2020 was not stolen since the proof is not good enough? Nobody could prove Stalin stole elections so they were good too by your definition.
Allegations are not lies. They are also not proof.
Since we are currently talking Californika, proof is what is needed to convict a PERSON of the charges made against him in a court of law.
Name the vote harvester(s). That is a first step.
Name the person(s) who shifted votes from Bass to DSA.
In a specific precinct collect affadavits that prove the reported count in that precinct was impossible because the affadavits were for a different count. (In my experience, when properly told the implications of an affadavit, nobody lies. But some refuse to sign an affadavit.)