I am not really sure about devs checking the work of other devs. Maybe it is possible and viable. I just don't know.
I dont see any other options right now. They understand the material and the work.
One thing that might work is to have some kind of talks or interviews where projects receiving funding periodically go to give an update to the community. And the community can ask questions.
The problem is that the community doesnt understand the work. We could be told anything in a convincing manner and we would believe it because we dont understand the relations between effort, work, pay.
The scrutiny needs to come from devs themselves. A self check system or someone actually paying attention to whats done and pointing to it.
What about giving the money after they showed work done.
That would make it logic and simple.
Not like they wouldnt be paid but the otherway around is obviously and also logically a big issue.
We pay for a service done and dish we ate.