To really have proof, you'd have to match each and every ballot to a specific voter. That ain't gonna happen, and I'm not sure I'd want to be able to do that. That's how you get Saddam Hussien's 100% of the vote.
However, we know that Trump was leading in all of the battleground states by at least 100,000 votes at midnight on election day. Then, the observers were thrown out and supposedly counting stopped. But, next morning though, Biden was leading.
And some of the Trump totals actually went backwards! The mail-in votes that were received and counted after midnight were about 83-17% for Biden, not impossible, but highly unlikely. So, it's very, very fishy to an honest thinking person.
Was that also the case for the drop box ballots?
Yes. The red mirage. We showed up to vote on the Election Day while the Democrats insisted on mail in ballots. Okay so why did they insist on mail in ballots? They saw this as an opportunity to stuff the ballots. They took advantage of the COVID-19 pandemic. They were able to manipulate their voters to "play along" so it would help to cover for their cheating.