A natural singing voice isn't strained or pinched. So often, when singers try to emulate a "folk sound" they constrict their larynx so that the tones are thin and reedy. The solution is to relax the larynx, work for relaxation in general and find the natural balance of your singing voice with enough proper breath support.

The "choirboy" sound is an interpretive affectation.

It's important not to force the voice for it to be focussed with full vowel sounds.

The worst possible thing you can do is to try to sound like a field recording of a traditional singer because it's not natural to you and becomes an imitation.

Imitators abound in the folk music field and always sound affected and phony.

Sing like your voice is, not like someone else's.