If you must have assistance for people who can't mark a ballot paper due to disability, have the machine mark their ballot paper and count it as per normal.
Everyone knows what cheating looks like in ballot counting, the evidence of ballot stuffing is harder to hide, easier to spot and generally understood.
Even if electronic voting could be made absolutely secure, safe and fair it would not be understood by most voters, that means it really shouldn't be used. But as pointed out, it can't be made secure so just don't use it. Ban it. Destroy it. Elections must be fairly counted, seen to be fairly counted and understood how they are counted fairly.
