Looks like the warning here boils down to the source code for the machines being available to Trump's team due to their post 2020 election legal proceedings. It seems most states now perform Risk Limiting Audits to ensure statistical conformance of digitally counted votes to manually counted, voter verified paper ballots. Is there any reason to believe those wouldn't be a reasonably effective canary to indicate digital tampering?
Georgia has already certified, ostensibly performing their RLA prior as I understand is now required by their laws. Pennsylvania should be soon.
I certainly agree that the source being available to one party and not another is an unacceptable compromise of our elections integrity that needs to be addressed though. Australia's digital polling system's source is publicly available for audit. Security by obscurity is an especially weak argument to keep from publishing ours when one party with incentive to tamper already has it.