In the conference today, they actually mentioned this. They stated the USB cards that dominion admins replaced were used to take votes here or there (they also mention having photo evidence of them doing this, dunno why they didnt show tho, maybe some legal reason?).
Then, on election night, they realized Trump was winning more than they thought, so that is when they brought in huge batches of fraudulent ballots to make up for it. Which is why they had a computer forensic analyst "testify", who is also a distinguished, retired military. He also laid out a clear and quick way to verify these if given the opportunity. They also mention how if given the physical ballots, they can quickly analyze the ink used to fill them out, etc.
They also mention this for other swing states as well, which is why in the middle of the night, there were huge ballot drops, many with votes only for Biden, without other democrats being voted for.
This is just what they presented though. Not sure how they would proceed.