The cleanest recordings involve playing each part separately.
When you solo a track all you hear is the voice or the guitar. No leakage.
A one pass recording is a "live" recording.
The problem with recording live with a LDC mike is it picks up everything in the room.
If you make a mistake on either you vocal or your guitar you have to re do the whole song over and over until it's the way you wanted it.
To diminish this you have to isolate each part as best you can.
I would use a dynamic mike like a Beta 58 to isolate the voice more.
And plug the guitar in direct.
You just missed a sale on mike cords from Musicians friend yesterday. $9.99 for a Rapco 25'.
I buy 80% of my gear from Tom Lee music. I usually get a better price because they know how to keep me happy as a customer. And I don't pay shipping which is terrible in Canada.
The above $9.99 mike cord is $24 at check out for me. It's 19.99 if I go in the store.
I don't believe anyone here would be recommending a Behringer mike. For low price points look at the CAD mikes.