>IANAL, but isn't champerty permitted (or not prohibited) in almost every state?

Nope.

Third party lending as a broad policy trend has certainly opened up over time, but some states still have the restriction, others have reformed it, others call it a different thing and some have abolished it.

Is the risk substantial in your specific case? Maybe not. Maybe it is. Just know there's a risk there and you're the one eating it.