Even if it is overturned, it can take away Trump's right to campaign long enough to sway the election.
They can't take away Trump's right to campaign. Even if they do jail Trump, and that's a big if, Trump will have his own wing of the prison to accommodate his Secret Service protection. There is nothing to stop journalists from interviewing him during visiting hours. It will be a very different situation than if you or I were jailed.
It's true that some states will remove Trump from the ballot, but those states are mostly blue states Trump is going to lose anyway. Can you remember the last time Colorado voted red? And of course we can still write him in. If this trial was a plot by the left to stop Trump from winning a second term, it's not a very good one.
Intentional election interference while claiming they are not, while they tell the lie that Trump is doing it. It might not have the effect they want, but that is no excuse.