(1) Identify ballots with sole vote cast for Biden
(2) Identify the state representative (not Congress, state = small districts) for the precinct.
(3) Verify that the state representative candidates on the ballot match the state representatives that should be on ballots in the precinct.
(4) Disqualify as fraudulent any ballots where the state representative candidates and the precinct do not match.
(5) Trump/Pence is re-elected.
Sorry to be the bearer of bad news, but your scheme blows up at step 3.
Atlanta, Detroit, Philadelphia, Pittsburgh, and other major cites centralized the processing of absentee ballots.
This means that ballots from several voting precincts were combined into one facility, so a ballot good in any precinct that central facility serviced would be considered 'valid' under your scheme.
And if a ballot didn't match any of the precincts that the central processing facility served, then that ballot would have been rejected by the vote tabulation readers as invalid, because the form of the ballot didn't match the programming.
This would still catch fraudulent votes in other towns, suburbs and other states.
There are enough fish in the ocean that you don’t need to catch all of them, only a decent number.