Here’s a radical idea: hire the top 4 candidates on a probationary period. Have them work remote and with the same requirements and blind to each other.
Then you'd only ever get candidates that can afford to have a "maybe job" for a while until they get out with no pay check. I'd definitely not work for a company with that arrangement. Unless there is some guarantee they pay you until you land your next thing (within reasonable timeframes).
Nothing radical about it. People have reinvented this idea for decades. It's called "contract to hire," and it's a great way to hire a good line cook and a horrible way to hire a good software engineer.
Contractors are on a different time period contract. They’re treated as a temporary resource and more than likely will roll off than get hired. Filling an FTE role has a different motivation and so the probationary period would be very short, like several weeks.