I think the bulk of the fraud were ballots created after polls closed when they knew who voted and who did not and created ballots for the no shows, and the adjudicated switches of Trump votes to Biden votes. Those were the 2AM dumps. Also think there were some machines that had fractional voting enabled. Lots of analytical evudence for that.
Still low tech.. I think the whole kitchen sink was thrown at it.. but the main plan was to setup those over-votes in those 6 cities.. I don’t think it involved the IT in any way....