Polymarket would be really useful if the polls were reliable. There has been considerable fluctuation in their predicted probability. Just four days ago, they gave Trump a 68% chance of winning. Now, they are only giving him a 56% chance. It could easily fall to 50% by election day.

Elon is only sharing data when it favours Trump. I'm sure his aim is to build up the expectations of Trump's base. If Trump loses, which I strongly believe will be the outcome, they're going to be very upset. I doubt they will need any convincing that the election was rigged.

It is highly unlikely Russia would interfere. Trump would help them get a peace deal with Ukraine, but Trump is less favourable to Iran and China. Russia has other means of dealing with their opponents.