Sure, if it's somebody you know or trust who's saying this, then it's not disinformation; agreed about helping them contact election officials and/or other authorities, and if you think it's useful to amplify it, then I'm not trying to talk you out of it.
If it's not somebody you know or trust, then amplifying it is quite possibly helping out a disinformation campaign.
And in any case, amplifying individual claims is very different from the unsupported claims about "millions of missing votes", and that's what I am trying to talk people out of.
What's the evidence you find "literally incontrovertible"?
The comparison is apt though:
In 2020, almost all non-partisan voting rights organizations and election experts (as well as most Republicans, despite losing) were saying that there was in fact no evidence of widespread election fraud. So conservatives claiming election fraud were seen as conspiracy theorists who were spreading disinfo (either intentionally or because they really thought there was evidence).
In 2024, almost all non-partisan voting rights organizations and election experts (as well as most Democrats, despite losing) are saying that there was in fact no evidence of widespread election fraud. So ...