I like it how election officials cannot go into the booth with them but partisan “voting assistants” CAN.
The solution is to put TWO monitors into the booth, one Republican volunteer, one Democrat volunteer, and both observe the actions of the “assistant” helping the voter to cast a ballot as HE or SHE intends.
That's exactly how we handled it when I was an election officer, except it wasn't volunteers. It was the Chief election officer and Assistant Chief; they are required by law to be from opposing parties.