Aside from cryptographically sound and open source end to end verifiable options there is one simple alternative still used in many other countries and jurisdictions:

1. voters mark paper ballots 2. observers from all parties watch the counting 3. results are tallied publicly

Yes, this is very much feasible; and no, this is not the right domain to be ingeniously efficient and cost sensitive. US being the richest country in the world or some such, etc..