I think it's about being overly critical. I often have trouble liking my voice and have
never really liked it on recordings. Yet, I work pro.

Instead of concentrating on pitches, rhythm and the mechanics, go for the text. In folk music, this is what it's all about. An acting class would help here.

A lot of what passes for good voices in the folk field is debatable but who cares?

What you are saying is often more important than how.

Still, it never hurts to protect your voice by studying natural vocal production with a good teacher.

Take the pressure off and sing from your heart. If you are in the song, they will listen.