I agree that mail in voting is a vehicle for fraud. But I disagree about "over voting".
The charge was in over 800,000 ballots being case for a little over 400,000 voters. The truth of the issue is the ballots cast were counted off the papers printed (which "doubled the votes") but not really as the papers were not actual votes. This was only in Gwinnett County due to their process (which differs due to a requirement of the voter cards being printed in English and Spanish, with over 97% of voters returning both cards). This was only an issue in Gwinnett County because it is the only county in Georgia that falls under Section 203 of the Voter Right's Act). The "proof" was from the ballot counts prior to processing (the initial count showed double votes, but when processed the two cards were reconciled into one vote).
So this is a good example of propaganda. People have "evidence" in terms of the screen shots of the cards being counted twice and ignore that this was prior to the votes being processed. It is partially true because the ballot numbers are reported correctly (there were a lot more votes than voters) but it is false because it is not dealing with votes actually counted.
There are 7,233,584 registered voters in Georgia. of these 4,997,716 voted.
There were no counties where the number of votes counted were greater than the number of voters in that county.
It was just propaganda.
This is part of the reason President Trump shares some of the blame for the riot at the Capital. He relied on propaganda to keep his base stirred up. To be fair, so did Biden (more so, in fact). But when the certificates were being received was not a good time to continue the propaganda.